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to the ground, where they remain quietly for two or three weeks, gradually swelling and changing form. “At this time the pupa state is assumed, but not by shedding any skin, as do true insects in undergoing their transformations. New legs, feelers, and mouth-parts form under the old skin, which, with its now useless legs, distends so as barely to cover the new parts, which are all appressed to the body, very much as in the pupa of a beetle.” Finally, both the distended larval skin and the new one that incases the pupa burst, and release the mite in its eight-legged adult forn. It appears that from the time this mite hatches, through all its growth and changes, but one molt takes place. The adult mite passes the winter in the ground, and is active whenever the temperature is a few degrees above freezingpoint. Professor Riley has also reared Trombidium muscarum Riley from the larva which lives on the common housefly. He also figures and describes the transformations of Hydrachna belostomce Riley, an aquatic mite which usually infests the large water-bug (Zaitha); as many as 500 sometimes occurring on a single bug. They fasten themselves and penetrate the chitinous skin of their host with their maxillæ, which form a long, pointed thread. The body becomes sac-like, and transforms into the pupa state within this sac, which finally bursts to release the adult mite. This bag-like larva was looked upon as an egg by many old authors, and was made the type of the genus Achlysia by Audouin. Mr. Riley's article is printed in advance from the Report of the United States Entomological Commission.

The development of the crayfish has been freshly studied by Reichenbach, who supplements the works of Rathke, Lereboullet, and Bobretsky. He has found that many of the endodermal cells of the ordinary coluninar form are lobed at the end towards the yolk, and give off more or less fine threads of protoplasm, which pass between, and in some cases surround, the yolk spheres. These cells evidently absorb the nutritive matter of the yolk, “not by a passive process of diffusion, but by an active process of ingestion, the food particles being immediately 'plunged into the live ing protoplasm of the cell,' and there digested.” This active swallowing of particles of the yolk by embryonic cells was first observed by Lankester in the egg of the cuttle-fish.

The mode of moulting of the integument and lining of the crop and proventriculus, or fore-stomach, of the Orthoptera has been studied by Wilde. On the histological processes in the moulting of animals in general we have the previous works of Cartier, Braun, and Kerbert. In the reptiles as well as in the Astacus, or crawfish, moulting of the skin is effected by its being pushed off, in the first place, by fine cuticular hairs, which afterwards disappear. Exceptions to this mode only occur in the reptiles on certain parts of the body, as, for example, on the underside of the scales and the capsular skin of the eyes of reptiles; in the Astacus, the faceted cornea, the eye-stalk, and the inner lamellæ of the fold of the carapace over the gill-opening. In the locusts and grasshoppers the teeth arming the crop and fore stomach, though primarily of use in triturating the food, especially in the crop, are secondarily useful in loosening the enticle lining those parts of the digestive canal. As soon in the Orthoptera as the old cuticle is loosened and stripped off, there is the new cuticle completely formed under it. It is at first completely transparent, but takes on, after a few days-probably through the influence of the air, which passes through very fine tracheal twigs under the layers of epithelium—the characteristic yellow-brown color of the chitine. The secretion of the new cuticle must follow with great rapidity. It does not take more than one or at least two days in developing

BOTANY.

By Professor W. G. FARLOW,
Boylston Hall, Harvard COLLEGE, CAMBRIDGE, Mass.

There has been a very general activity during the present year on the part of botanists, as is shown by the large number of papers published in the different journals; although it would seem that the number of published books, particularly of those relating to flowering plants, was smaller than usual. As has been the case for some years past, the work done in Germany has been largely physiological and developmental, while in England and this country descriptive botany has been almost exclusively studied. During the year an unusual number of prominent botanists have died, of whom a considerable proportion were still in their prime, so far as activity in botanical pursuits was concerned. It is seldom that in one year four such prominent names as those of Alexander Braun and Hofmeister in Germany, and De Notaris and Parlatore in Italy, disappear from the ranks of botanists.

GENERAL.*

Phænogams. In striking contrast to what is usually the case, there is but little to be recorded in the department of descriptive phænogamy. The “Flora Brasiliensis” has been continued, one volume being devoted to the Graminece, comprising the suborder Panicece. The “Dictionnaire de Botanique,” conducted by Baillon, has also been continued by a second part, comprising several different orders. The Proceedings of the Linnean Society include a number of short articles on phænogams, the principal of which is an account by J. G. Baker, of the Iridece. The Journal of Botany contains also a number of short articles, among which may be noticed “Descrip

* The special report with regard to botany in America will be found on page 333.

tive Notes on a Few of Hildebrandt's East African Plants," by J. G. Baker and S. Le M. Moore; and “New Palms Collected in the Valley of the Amazon in North Brazil in 1874,” by J. W. H. Trail. The Botanische Zeitung contains an article by Dr. Robert Caspary, in which he describes a new species of Nymphæa, N. Zanzibarensis, and gives a synopsis of the species of the genus found in tropical Africa. In the same journal a new “ Classification of Palms," on the somewhat novel basis of geographical distribution is given by Drude. A third part of the “Prodromus Flora Hispanicæ,” by Wilkomm and Joann, has appeared; and Beccari has published, at Genoa, observations on some of the plants collected by him in the Malay islands.

Vegetable Anatomy and Physiology. Several important contributions have appeared during the year on this subject. First, in importance as well as size, is the “Comparative Anatomy of the Organs of Vegetation of Phænogams and Ferns,” by Professor De Bary, of Strasburg. The work consists of over six hundred pages, with a large number of wood-cuts, and is the most elaborate treatise on the subject since the days of Von Mohl. This volume is the third of the series entitled “Manual of Physiological Botany," published by Hofmeister in connection with De Bary and Sachs. Owing to the death of Hofmeister and other causes, it is announced that the work will not be carried further. The Botanical Laboratory of Würzburg has shown great activity, and several interesting papers have been published by Professor Sachs and his pupils. The most important article of this series is an essay on the “Arrangement of the Cells in the Youngest Parts of Plants." The paper is accompanied by diagrams, the object of which is to show that, whether the terminal growth takes place by means of what is generally known as a Scheitelzelle, a single terminal cell, or by a membrane, the cells are so arranged that a series of curves can be drawn through them in such a way as to have a common focal point, and to bear a definite relation to certain hypothetical axes. In those cases where the growth is by a single terminal cell, Sachs thinks that the growth is not highly developed, but the contrary. Sachs has also a paper on the porosity of wood, in

which he shows that the discoid markings of the spring and a part of tlie autumn wood are closed by a membrane, as was maintained by Sanio and Hartig. Vesque, in the Annales des Sciences, states, in an article on“ Water in the Stems of Ligneous Plants,” referring to a paper by Geleznow, that in some plants the wood is drier than the bark, and in other cases just the reverse; and the relative dryness depends upon what he styles the “transpiratory reserve.”

The anatomy of the root is treated in a paper by Holle, on the “Growing-point of the Roots of Dicotyledons,” in which he takes certain exceptions to the classification of roots according to their anatomical structure, as advanced by Janczewski in the Annales des Sciences. Absorption is treated by Vesque in a paper in the Annales des Sciences, in which he calls to mind the difference between exhalation and respiration. In the study of the crystals and albuminoids of plants, we would mention the discovery by Kraus of inulin in orders other than the Composite, in which it was previously known to exist. Kraus notices its occurrence in several species of the orders Campanulacece, Lobeliacece, Goodeniacece, and Stylidec. Harz has discovered in the testa of Spergula vulgaris and S. maxima a new fluorescent substance, to which he gives the name of spergulin. Anatomical studies in relation to limited groups are furnished in the papers of Koch on the "Development of the Seeds of the Orobanchacece,” and by Kamienski on the “Development of the Utricularice," the former of which appeared in Pringsheim's Jahrbuch, and the latter in the Proceedings of the society at Warsaw.

The work of Darwin on the “ Effects of Cross- and Selffertilization in the Vegetable Kingdom,” although in reality published in 1876, has not generally reached the public until the present year. It is giving it the highest praise in saying that it is not inferior to any of his previous works in thoronghness and scientific precision. From the mass of details which it contains, it is not likely to be thoroughly read by the public, who will be satisfied with the review of the work given by Professor Gray in the American Journal of Science for February, or that in the Journal of Botany for March. The careful tabulation of accurately conducted investigations shows the decided advantage possessed by cross-fertilized plants. Of course, the book has given rise to violent discussions; but

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