the class Pholidoti. The sub-tribe Ascalabotes, according to him, embraces the Iguanide as well as Geckos. M. Latreille (1801-1825) seems to have adopted the views and descriptions of Lacépède in the first instance, and not to have gone much beyond a change of nomenclature in the last work published by him. M. Fitzinger (1826) makes his Ascalabotoïds consist of the genera Sarrubus, Uroplatus, Ptyodactylus, Hemidactylus, Thecadactylus, Ptychozoon, Platydactylus, Ascalabotes, Stepodactylus, and Phyllurus. Dr. J. E. Gray (1827-1834) arranges the following genera under the family Geckotida:-Hemidactylus, Platydactylus, Gecko, Pteropleura, Thecadactylus, Plyodactylus, Phyllurus, Eublepharis, Cyrtodactylus, Phyllodactylus, Diplodactylus, and Gehyra. Wagler (1830), under the family name of Platyglossi, makes the Geckotide consist of the following genera :-Ptychozöon (Kuhl), Crossurus (Wagler-Uroplatus of Duméril in part), Rhacöessa (Wagler one of Duméril's Uroplati), Thecadactylus (Cuvier), Platydactylus (Cuvier), Anoplopus (Wagler), Hemidactylus (Cuvier), Ptyodactylus (Cuvier), Sphæriodactylus (Cuvier), Ascalabotes (Lichtenstein), Eublepharis (Gray), Gonyodactylus (Kuhl), and Gymnodactylus (Spix). 1, Dr. Cocteau (1835) arranges the Geckos into six divisions:Platydactylus, containing five subdivisions, represented in part by Anoplopus of Wagler, Phelsuma (Cocteau), Pachydactylus (Wiegmann), Ptychozöon (Kuhl), and Pteropleura (Gray), with others resting principally upon the absence or presence of pores before the cloaca, and the development of the claws; 2, those Geckos which correspond to Thecadactylus of Cuvier; 3, Hemidactylus; 4, comprehending Ptyodactylus (Uroplatus, Duméril; Rhacöessa, Wagler; Crossurus, Wagler); 5, Sphæriodactylus, comprehending Diplodactylus (Gray) and Phyllodactylus (Gray); 6, Stenodactylus (Eublepharis, Gonyodactylus, Gymnodactylus, Cyrtodactylus, Pristurus, Phyllurus). M. de Blainville (Nouvelles Annales du Muséum,' April, 1836) places the family of Geckos at the head of the family of Saurophians. The species forming the genus Platydactylus of Cuvier he designates as Geckos; those ranging under Hemidactylus as Demi-Geckos; the Plyodactyli as Tiers-Geckos; the Stenodactyli as Quart-Geckos; and the Gymnodactyli as Sub-Geckos. The following cuts will convey an idea of the form of some of the Geckotida : 1, a 1. Gymnodactylus Miliusii (Cyr, dactylus Miliusii, Gray). 1, a, the underside of one of its toes. (Duméril.) The following is a synopsis of the genera and a list of the species, as given in the 'British Museum Catalogue,' 1845:— Synopsis of the Genera of Geckotidæ. I. Toes dilated, with 2 rows of membranaceous plates beneath, under the dilated part. 4. Last joint of the toes short, inflexed, sheathed in the notch between the front of the 2 series of plates. Claws 5-5. a. Toes dilated, ovate, with 2 series of transverse equal plates beneath. 1. Thecadactylus.-Toes half webbed. Femoral pores none. Tail uniformly granular. b. Toes linear, truncated, middle of the toes with 2 rows of square plates beneath, the 2 terminal plates larger. 2. Edura.-Tail subcylindrical, with square scales, unarmed. Toes all with 2 rows of small plates beneath. 3. Strophura.-Tail cylindrical, with 2 rows of spines above, tip revolute. The 2 middle toes with 2 rows, the rest with 1 row of plates beneath. c Toes linear, truncated, middle of toes with a single series of plates beneath, 2 terminal plates larger. 4. Diplodactylus.-Terminal pair of toe-plates convex, rounded at the end. Back and tail granular, uniform. 5. Phyllodactylus.-Terminal pair of toe-plates thin, square at the end. Back and tail tubercular. d. Toes slender, dilated at the end, with 2 diverging series of 6. Ptyodactylus.-Toes free. Body simple. Tail round. 8. Caudiverbera.-Toes webbed. Tail and back with a B. Toes, last joint slender, compressed, elongate, produced, clawed, free from the dilated penultimate joints. a. Thumb with a compressed clawed terminal joint, like the toes. 9. Hemidactylus.-Tail rather depressed, angular above, with cross rings of spines, lower edge simple. Toes free. 10. Velernesia.-Tail rather depressed, angular above, with cross rings of spines, lower edge denticulated. Toes half webbed. Skin of sides and limbs lax. 11. Doryura.-Tail depressed, uniformly granular, denticulated on the edge. Toes free. Sides and limbs simple. 12. Platyurus.-Tail depressed, uniformly granular, denticulated on the edge. Toes half webbed. Sides and limbs with a thin membranous expansion. 13. Leiurus.-Tail cylindrical, uniformly granular, tapering. Toes slightly webbed. Sides and limbs simple. 14. Crossurus.-Tail cylindrical, granular, with a festooned fringe on each side. b. Thumb with a compressed, clawless, terminal joint. 15. Boltalia.-Toes free. NAT. HIST. DIV. VOL. II. 25. Ptychozoon.-Toes webbed. Head, body, and tail with membranes on the side. c. Claws 2-2. All but the two middle toes without any compressed last joint. 26. Tarentola.-Lower rostral shield very long. d. Claws none. Toes all without any compressed last joint. 27. Phelsuma.-Toes dilated, ovate. Tail rather contracted. 28. Pachydactylus-Toes slender, short, apex rather dilated. 29. Sphærodactylus.-Toes slender, with a single rounded disc at the tip. D. Toes and thumbs clawed, slightly dilated below at the base, the two or three last joints compressed, angularly bent, the membranous plates beneath the toes transverse, smooth. a. Toes rather thick, tapering. Tail round. 30. Naultinus.--Tail cylindrical, tapering, granular. Preanal pores in 2 or 3 cross series. Back granular. Eublepharis.-Tail cylindrical, ringed with cross series of tubercles. Back tubercular. 31. 32. Homonota.-Tail cylindrical, tapering, granular. Preanal pores none. Back scaly. 33. Pristurus.-Tail compressed, dentated above. b. Toes elongate, slender, compressed, versatile, joints bent at angle. 34. Goniodactylus.-Tail round, tapering, granular. Scales granular. Preanal pores none. 35. Cyrtodactylus.-Tail round, tapering, with rings of tubercles. Back with rows of tubercles. Preanal pores in 2 parallel rows. 36. Heteronota. Tail round, tapering, with rings of tubercles. Back tubercular. Preanal pores in an arched series. 3 P Diplodactylus vittatus, the Yellow-Crowned Diplodactyle. D. ornatus, the Beautiful Diplodactyle. West Australia. D. marmoratus, the Marbled Diplodactyle. Australia. D. bilineatus, the Two-Lined Diplodactyle. D. lineatus, the Lined Diplodactyle. Cape of Good Hope. D. Gerhopygus, the Naked Diplodactyle. Phyllodactylus pulcher, the Phyllodactyle. P. tuberculatus, the Large-Tubercled Phyllodactyle. Uroplates fimbriatus, the Famocantrata. Madagascar. U. lineatus, the Sharp-Tailed Famocantrata. Hemidactylus trihedrus, the Triangular-Tubercled Hemidactyle. H. maculatus, the Spotted Hemidactyle. H. Brookii, Brooke's Hemidactyle. H. depressus, the Groove-Tailed Hemidactyle. H. verruculatus, the Warty Hemidactyle. H. fasciatus, the Banded Hemidactyle. Shores of the H. Mabouia, the Brazilian Hemidactyle. Brazil. H. mercatorius, the Wandering Hemidactyle. H. frenatus, the Streaked Hemidactyle. Ceylon. H. Leschenaultii, Leschenault's Hemidactyle. Ceylon. H. vittatus, the Streaked-Cheeked Hemidactyle. Borneo. H. Peruvianus, Wiegmann's Hemidactyle. Peru. Doryura Bowringii, Bowring's Hemidactyle. D. Garnotii, Garnot's Doryure. South Sea Islands. Platyurus Schneiderianus, the Platyure. Java. Pachydactylus ocellatus, the Eyed Gecko. Cape of Good P. maculatus, the Spotted Pachydactyle. South Africa. S. punctatissimus, the Lined Sphærodactyle. Martinique. S. nigropunctatus, the Black-Dotted Sphærodactyle. South S. Richardsonii, Richardson's Sphærodactyle. America. N. Grayii, the Long-Toed Kakariki. New Zealand. Homonota Guidichaudi, Guidichaud's Scaled Gecko. Chili. G. Australis, the Australian Angular-Toed Lizard. Australia. G. alboangularis, the White-Throated Angular-Toed Lizard. G. ocellatus, the Eyed Angular-Toed Lizard. Tobago. C. pulchellus, the Beautiful Cyrtodactyle. Singapore. Cubina fasciata, the Banded Cubina. Martinique. C. D'Orbignii, D'Orbigny's Cubina. Chili. Gymnodactylus Geckoides, the Gymnodactyle. Shores of the Mediterranean. Phyllurus platurus, White's Phyllure. Australia. P. Milinsii, the Thick-Tailed Phyllure. P. inermis, the Spineless Phyllure. Australia. Stenodactylus guttatus, Wilkinson's Stenodactyle. Egypt. GEDD. [Esox.] GEDRITE, a Mineral occurring in crystalline masses having a fibrous radiated or lamellar structure. Its colour is clove-brown. The streak gray or yellowish. The lustre submetallic, feeble. Hardness not above 5. Rough. Specific gravity 3.26. It occurs in loose stones near Gèdre in the Pyrenees. It has some resemblance to Anthophyllite and Hypersthene. It has the following composition : GEHLENITE, a Mineral occurring in square prisms. It has a gray colour, and is nearly opaque. The hardness is 5 to 56. The specific gravity 2.9 to 31. It has the following composition : It fuses with borax with difficulty. It gelatinises with muriatic acid. GELA'SIMUS, a genus of Brachyurous Crustaceans. [OCYPODIANS.] G. Australis, the Swan River Gehyra. Swan River. Ptychozoon homalocephala, the Fringed Tree-Gecko. Java. Amongst the component parts of all organised bodies the most frequent is the cell. Modified in an infinite variety of ways, it gives rise to the innumerable varieties exhibited both by plants and animals, in the external form, the structure, and consequently the functions of their organs. In the vegetable kingdom the substance employed in T. Delalandii, Laland's Tarentola. Madeira; West Coast of the construction of these cells is cellulose combined with a little Africa. T. Americana, the American Tarentola. North America. T. Borneensis, the Bornean Tarentola. Borneo. T. clypeata, the Shielded Tarentola. Glasgow. protein. In the animal kingdom it is gelatin. The case is very similar, although the elementary form of the tissue and its chemical characters are different. In animals we must distinguish between the persistent and the original cellular substance. The original in all Mauritius. probability varies in different cases, while the persistent exhibits a Mada- constant and general character. The persistent tissue is consequently a secondary product, and in this respect differs from the cellular substance in plants, which is a primary or original one; neither has it an actual cellular form like the latter. There is however a resemblance between the two in several points, especially in relation to the large proportions in which they both exist, and to the several functions which they perform. Gelatigenous substance is so widely diffused over the body that it would exhibit the entire shape of the principal organs, even if all other constituents were separated. It constitutes the skin, the serous membranes, the cellular sheaths of the muscles, the organic portion of bone, and many other substances. It is insoluble in cold water; acetic acid renders it transparent and bulky; tannic acid renders it solid, and prevents its putrefaction; and when boiled it forms a jelly. It is in consequence of the last property that it has received the name of Gelatin. The gelatigenous substance (as in skin, areolar tissue, serous membranes, &c.) is insoluble in cold water, and on boiling is merely physically and not chemically altered. In the process of boiling nothing is taken up and nothing separated; the alteration being similar to that undergone by starch when heated in water. The composition of Gelatin is represented by the formulaC13 H10 N2 05 whether obtained from hartshorn, from isinglass, or from silk. Both boiled and unboiled cellular tissue (after its conversion into glue) combine with tannic acid, and produce compounds which are insoluble in water and resist putrefaction; hence the power of all medicines containing this substance to heighten the tone of the system. The protein-compounds in a similar manner form hard and coherent compounds with tannic acid. Peruvian and willow bark, catechu, and many other astringent medicines produce compounds of this nature in the organism. On boiling Gelatin in water for a long time we obtain a hydrate of gelatin, which no longer gelatinises: its composition is 4 (C1, H10 N2 01)+aq. This peculiarity should be remembered, for the compound is likely to be formed in the preparation of broth, and in the application of Papin's Digester to cooking; and it is regarded by Mulder as doubtful whether this hydrated gelatin can be again converted in the organism into nutrient matter, and whether it may not produce noxious substances in the body. [FOOD.] 13 2 As Gelatin has never yet been discovered in the vegetable kingdom, there is every reason to believe that it is solely produced in the animal body. It is most probably formed from the decomposition of the protein in the blood, through the action of the alkali in the serum, and the oxidising influence of the atmosphere. We are likewise imperfectly acquainted with the products of the decomposition of the gelatigenous tissues in the body. Out of the body we know that by the influence of oxidation on gelatin prussic acid is formed, and that, by the action of alkalies, gelatin-sugar, leucin, and extractive matters are produced, while ammonia is disengaged, and an alkaline carbonate formed. Finally, when boiled in dilute sulphuric acid, it yields extractive matters with either gelatin-sugar or leucin. Since leucin is also produced from albumen when decomposed by potash, we perceive an intimate connexion between that proteincompound and gelatinous matters. Besides the gelatin obtained from cellular tissue and serous membranes there is another kind which has many of its properties, but differs from it in composition. It was first described by Müller under the name of Chondrin. It is obtained from the cornea, and from those cartilages which do not ossify by boiling them in water. Its composition is 10 (C2 H20 N, 014) + S. Gelatin is extensively employed in the arts in the form of glue, and constitutes the basis of leather. It is found pure in the air-bladder of some fishes, and on being cut up constitutes isinglass. When purified it can be formed into plates of almost glass-like transparency, and when coloured is employed for making artificial flowers and many other ornamental objects. Its relation to the other substances in the animal body are considered under PROTEIN. GELDER ROSE, or rather, GUELDRES ROSE, a double variety of the Viburnum Opulus, a marsh shrub, common in this country and all the north of Europe. The name of this variety is supposed to indicate its origin in the Low Countries: it is also called the Snowball-Tree, in allusion to its large white balls of flowers. [VIBURNUM.] GELIDIUM. [ALGE.] GENERATIONS, ALTERNATION OF. During the course of the development of many of the lower animals from the ovum to their adult condition, they not only pass through various forms, as is seen in the Insect tribes [INSECTS], but at certain stages of their growth they possess the power of multiplying themselves. The individuals which exhibit this phenomenon have been called 'nurses,' and the whole series of phenomena connected with this mode of reproduction have been called by its first expounder, Professor Steenstrup, an 'alternation of generations. This phenomenon has been particularly observed in the Acalephæ, Entozoa, Polypiferæ, Salpa, and Vorticella. In the various articles on these families of animals, their mode of development is described. As however this subject is one of general interest, and very imperfectly understood, we take the opportunity of | reproducing here Professor Steenstrup's general remarks on this subject, from a translation of his work published by the Ray Society:"The mode of development by means of 'nurses,' or intermediate generations, is thus seen to be no longer an isolated phenomenon in nature. The circumstance of an animal giving birth to a progeny permanently dissimilar to its parent, but which itself produces a new generation, which either itself or in its offspring returns to the form of the parent animal, is a phenomenon not confined to a single class or series of animals; the vertebrate class is the only one in which it has not yet been observed. It would consequently appear that there is something intrinsic in this mode of development, and that it occurs as it were with a certain necessity; on which account it will undoubtedly soon be recognised to a greater extent and more generally. It should no longer be considered as something paradoxical or anomalous (as we have hitherto been too much inclined to deem both it and the phenomena in which it is exhibited), it must be in harmony with the rest of development in nature, in which the fundamental principle of this course of development must also be elsewhere expressed, although it may be displayed in a form under which we shall less readily perceive and recognise it. This is seen when we trace the mode of development in question more widely through nature; and whilst contemplating it through the phenomena in which it is manifested, we comprehend it in its true light. "If we collect and regard in one view the whole system of development by means of 'nursing' generations, as it is exhibited in the Bell-Shaped Polypes (Campanularia), the Claviform Polypes (Coryne), Medusa, Salpa, Vorticella, and Entozoa, it appears as a peculiar and consequently as an essential feature in this course of development, that the species (that is, the species in its development) is not wholly represented in the solitary, full-grown, fertile individuals of both sexes, nor in their development; but that to complete this representation, supplementary individuals, as it were, of one or of several precedent generations are requisite. Thus, the distinction between this course of development and that which is generally recognised in nature, in which the species is represented by the individual (of both sexes) and its development, is the want on the part of the individuals of a complete individuality as representatives of the species, or of a specific individuality, if I may so express it. If now we agree to regard such an incompleteness in the individual as the essence of this development, we shall comprehend its significance in nature when we thoroughly consider this course of development in its various periods, throughout the above-mentioned families, how it begins and advances, so that at last we discover to what it tends. I believe, also, that we might trace even now this development by means of precedent, preparatory generations of 'nurses' in its peculiar course and advance, notwithstanding the paucity of instances adduced in the foregoing pages, and the many gaps in the series of observations. Thus we see the greatest incompleteness and the highest degree of mutual dependence in the Campanularia and similar Polypes, in which the generations representing the unity of the species are very unlike each other, and in which all the individuals are fused, as it were, into an outward unity, or into a set of Polypes. They exist, organically connected with each other, and are normally free only in their first generation, and indeed only in their earliest stage of development, and only for a short time, since the free-swimming ciliated embryo swims about in the water at most for some hours, in order to find a suitable place for the foundation of a new polype stem. In the Coryna, or claviform Polypes, the organic connection between the individuals and generations is rather more lax; the perfect gemmiparous or ovigerous individuals are usually quite free, often even at an early age (Coryne fritillaria, Corymorpha), so that they do not attain their full development until after their separation from the nursing' generation. In the Medusa and Salpæ, the generations which are connected together into one whole, become more like each other; the first generation of the Medusa is still fixed but more active and mobile in its parts; the individuals of the perfect generation leave the 'nursing' animal while still very small, and undergo remarkable changes after they have become free and are swimming freely about; both generations of the Salpa, finally, are free, and free swimmers, only the individuals of one of them are organically connected with each other; they have however no common organs (in the full-grown state), and if my explanation of the alternate generation of the compound Ascidians is correct, we have in that instance precisely the development of the Salpa at a somewhat lower stage; the individuals of the one generation are organically connected, without having a common organ; but both generations are fixed. "In the class of Entozoa a similar progressive attempt at becoming free and accomplishing a perfect growth appears evident to me. "In the Cestoidea the generation of perfect individuals, constitutes externally a unity; they are only successively detached from each other as the term of their existence approaches, and their whole existence is throughout connected with the nursing' animal. In some of the Trematoda, the later generations remain within the earlier until they have attained their full development; in others they forsake them in an earlier condition, are free, and free swimming, and undergo a complete metamorphosis; in some of these latter, the earlier generations are transformed into motionless, and, as it were, lifeless cysts, 951 GENERATIONS, ALTERNATION OF. GENERATIONS, ALTERNATION OF. 952 Thus there are in a hive of bees, individuals which are employed almost wholly in the feeding of the larvæ (foragers), whilst others do scarcely anything else than collect wax and build cells (workers). In ant-hills, one set of the feeders is constantly employed in conveying the larvæ from one place to another, according as they require a greater or less degree of warmth, &c., whilst others are engaged in building the passages or earth-cells, and in making excavations around the habitation. Among the Termites also we are acquainted with several forms of 'feeders,' constituting particular tribes or classes; the description of labour, however, which each of these classes performs, is unknown. It is known, however, that a form with a large head and strong jaws is always posted at the entrance of the artificially constructed dwelling, and keeps guard there as soon as any disturbance is remarked, and thus constitutes the safeguard not only of the young but of the whole community. "Now in the cases in which the more perfect development of the progeny is promoted, either by means of nurses' or of 'feeders' (under which latter term we understand special individuals devoted to the actual care or nourishing of the young, which office they fulfil by a conscious activity), we see that nature always has in view the production of a multitude of individuals to whose life or care is then committed the perfecting of a later generation or progeny, consisting of less numerous individuals. This previous or preparatory multitude seems to consist invariably of females, the males being apparently excluded from any participation in the office, on which account the males of all the animals among which the system of 'nursing' or of feeding' obtains, constitute a very subordinate number. That the 'nursing' should be committed to females alone appears to us very natural, since we are acquainted with an organ in them whose natural function would be to perform that office. The generative organs are, indeed, in perfect (female) individuals divided, as it were, into two parts of very distinct natures; the ovarium for the preparation of the germ and the production of the egg, and the oviduct and uterus, in which the ova are, as it were, incubated, and the germ and embryo sufficiently developed to allow of its being born. Now, it is actually the case that no true ovary has been discovered in the 'nursing' generations; on the contrary, the germs, as soon as they are percep tible, are situated in organs which must be regarded as oviducts and uteri, as, for instance, in the most perfect 'nurses' we are acquainted with, the Aphides. In the nurses' of the trematode larva, the Cercaria echinata, I have remarked that the germs in their earliest condition are collected into an organ at the root of the tail, which may probably be regarded as a uterus, and that they appear to distend this organ gradually to the size of the whole body. The accurate anatomical researches of Professor Eschricht on the Salpa also show in the most precise way that the associated brood of the Salpa does not originate from ova, but that, as germs which are arranged in a definite manner between the walls of a hollow organ, it is contained in what can in no case be an ovary, and which the author has termed a 'germ-tube.' This organ lies in a cavity which may probably be considered very nearly a uterus, which is however always, as it were, a secondary receptacle for the germs; but in the present instance it cannot be shown that they have occupied any previous receptacle or place of formation. whilst in others they remain free and active (the 'nurses' and 'parent nurses' of Cercaria ephemera and C. echinata), but retain during their whole life a form which, at most, resembles the larvæ of the more perfect generation. In this way an advance in a certain direction may indisputably be observed. At first all the generations constitute a unity, not merely as regards the interior, but also with respect to the exterior: they form a stationary colony; after which the generations are detached more and more from each other, and become at the same time more free; and, finally, all the individuals constituting the generation are separate from each other, and acquire the power of free locomotion. In this latter stage, or that of freedom and perfection, we found the development of animals which are certainly no longer attached to inanimate objects at the bottom of the sea, but live buried in other animal organisms, and belong not to the sea but to fresh water. In a still higher and more free stage than this we observe the development of animals which do not belong to the water, but to the air, as in that which occurs in the Aphides. The propagation of these creatures through a series of generations has been already long known. In the spring, for instance, a generation is produced from the ova, which grows and is metamorphosed, and without previous fertilisation gives birth to a new generation, and this again to a third, and so on, for ten or twelve weeks; so that in certain species even as many as nine such preliminary generations will have been observed; but at last there always occurs a generation consisting of males and females, the former of which, after their metamorphosis, are usually winged; fertilisation and the depositing of eggs takes place, and the long series of generations recommences in the next year, and in the same order. All the individuals are free, and enjoy the power of free locomotion, and undergo a metamorphosis. Here, however, we have before us aerial animals, and which are no longer parasites inhabiting other organisms; at most they are only externally parasitic, and on plants alone; the phenomena of this mode of development are no longer exhibited by Entozoa, but by Epiphyta. Nevertheless, the course of development is in itself similar; but in the external, more free, and nobler form in which it is now exhibited, the endeavour to attain something higher is manifest. Each link or generation certainly brings its offspring nearer to the perfection aimed at; but this approachment towards perfection is effected only by means of the 'nursing' by special animals, and is committed to the still and quiet activity of an organ, without the nursing animals themselves being conscious of it; it is a function merely, and not an expression of the will. In all parts of the animal kingdom we see instances of the still, quiet, and unconscious activity of the animal being developed into voluntary actions, which are undertaken by it from an internal, obscure, and irresistible impulse (or artificial impulse), as is the case in this instance. The development and mode of feeding or nourishing the young, exhibited in its course, of Bees, Wasps, Ants, and Termites, affords a direct example of the mode in which the care of the young is provided for, by the voluntary action of numerous individuals devoted to that object. Those of the young which are to be developed into the more perfect, fertile individuals are not protected in the body of the foster-parents, nor is their nourishment secreted by one of the organs; both protection and food are afforded them by means which are brought about by the conscious activity of the 'feeders.' The Wasp, for instance, or the Wild Humble-Bee, which has been impregnated in the autumn, and has afterwards sought a shelter to protect itself against the cold of winter, prepares a solitary habitation in which it builds cells and deposits its eggs. From the eggs proceed larvæ, but the insects into which these larvæ are metamorphosed, are not fertile; they are barren, and all their faculties are directed to the assisting of the parent animal in the better nourishing of the future brood, to which end some of their external organs are transformed, and to the erection of a better habitation and cells, into which they convey the eggs of the female, and the food of the larvae to be developed from them. Other cells, which contain a better sort of food, are erected for a later and less numerous progeny of eggs; and again in others, which are more roomy and provided with the best kind of food, but of which there are only a few, is the last brood of the female deposited. From the first kind of cells proceed the barren individuals, from the second the males, and from the third the females; after undergoing a metamorphosis, the males and females fly away, impregnation takes place, and the males die; the females however return, and the whole multitude of barren individuals, which at the same time perform the duty of feeding the young, build cells for their various progeny of eggs, and nourish the three forms of larvæ which proceed from them. In this way the inhabitants of the colony become very numerous; nevertheless they all die off in the winter: the fertile females alone remain alive, and propagate the species the year follow-propagation of the species, into a nisus impelling to the feeding or ing, under the same development of alternating broods, the earlier of which is always by far the most numerous, and assists in the development of the latter. In the colonies of Bees, Ants, and Termites, the same thing occurs; the many thousand individuals which constitute one of these colonies are principally 'feeders,' or individuals which have originated in the precedent divisions of the eggs of the females, and in these is exhibited, even with greater precision, a more marked division of labour in the feeding of the progeny; so that, out of the various precedent divisions, individuals apparently arise which assist in the development of the more perfect progeny in various ways. "From what we at present know, we may probably assume with some degree of certainty that the 'nursing' individuals are never themselves gemmiparous, but that they are born with germs in the organs in which the embryos are afterwards nourished; and from all this it appears as if the female generative organism were always divided in those cases in which development by means of nurses' occurs, so that as in the more perfect females an ovary especially is formed, so in the 'nursing' individuals a much-developed uterus is presented, in consequence of which, they, as individualised uteri, have assigned to them, as the object of their existence, the performance of the functions of a uterus, and their complete formation must thus necessarily precede that of the germs which are committed to their fostering care. We cannot readily perceive the reason, that because all 'nursing' individuals must be of the female sex, it should follow that all those individuals which feed the young should also be of that sex, and yet this seems to be the law. Anatomy shows us that the 'feeders' among bees, wasps, &c., and probably those of all insects living in regular societies, are females, whose sexual organs remain in an undeveloped state. They present scarcely the vestige of an ovary; the uterus is rudimentary, and all propagation consequently in the material way, so to say, is rendered impossible; the imperfection of the organ does not even allow of their acting as 'nurses,' and the propa gative instinct in a physical, corporeal sense passes into a will for the nourishing of the young; and the fulfilment of these impulsive duties is favoured by the peculiar transformation which some of the organs undergo at the expense of those intended for propagation, in order that they may become adapted to the bringing up of the young. Whence it follows that the development of the species in this case does not take place by means of several generations, but through several broods of the same generation. The reason of the great number of 'feeders,' and for the common good of workers,' so that they often constitute thousands, whilst the fertile individuals scarcely amount to hundreds, may be readily understood when we consider |