FULL exposition of the general and comparative structure of teeth may be found in standard works of Physiology and ordinary textbooks; but in explanation of the singular diversity of form and character in a mammal tooth as shown in the plate, it is necessary to describe generally the typical condition.

The teeth of vertebrates greatly differ in character, in the disposition of the tissues, structure, position, numbers, and adaptability, not only for seizing and macerating food, but as weapons of defence, attack, and instruments or tools subservient to the economy, and habits of the animal. They also denote age, sex, and are curiously adapted to the quality and character of food; to meet these and many other exigencies, their structures and condition necessarily divaricate into differences, to such an extent as to be subservient to use and functions; the shape, character and organisation of a tooth raises it to the importance of a zoological touchstone and element in classification, reaching the deepest researches of the palaeontologist; every class of the vertebrata-fossil or recent-may be distinguished by the moulding and contexture of this organ; notwithstanding that in the complex creatures of past ages, strange approximations, and combinations of class, exist; the recognition of an extinct Batrachian, the Labyrinthodon, was determined by the character of the convoluted folds of the dentine of its tooth.

No. 250.-OCTOBER 1885.

In the beautiful sections as now prepared for microscopical investigation, these differences are so admirably shown, as to raise them above "popularity," and elegant as they may be as attractive objects, to the student they are of deeper interest and educational value.

A typical tooth (human molar) may be said to consist of three constituents; in the centre a cavity enclosing a soft dental pulp, freely supplied with blood vessels and nerves; surrounding this is the dentine, the actual formed substance with radiating canaliculi, covered on the surface of the exposed parts by the enamel; surrounding the imbedded portion (the root or fangs) is a thin vascular structure, the cement, also rich in blood-vessels. A section cut horizontally would exhibit all these components; made transversely, the pulp cavity, the dentine, and enamel only would be revealed; such a preparation discloses a typical condition of the parts, but without deviating from the fundamental principle, varieties and modifications are found in lamination, solidity, contour, and distribution of the tissues. These diversities are found in every class, and extended modifications in species.

It is common knowledge that the horns of some animals, as the rhinoceros, are formed of a dense compressed mass of hairs, and the component parts of these compacted structures are easily distinguished by the microscope. Such cohesions are found in teeth, as seen in the plate. An infinite number, each with its distinctive character, may be aggregated into one mass; to external appearance it is a single tooth; on microscopical examination it is found to be a multitude locked together. This peculiar compound intertexture is common in the class of fishes, but somewhat rare in the mammalia. The object depicted in the plate is an instance of this peculiarity, and is thus described by Professor Sir R. Owen.

"Each tooth of the Cape Ant-eater (orycteropus) presents a simple form, is deeply set in the jaw, but without dividing into fangs; its broad and flat base is porous like the section of a common cane. The

T

canals to which these pores lead contain processes of a vascular pulp, and are the centres of radiation of as many independent dentinal tubules. Each tooth, in fact, consists of congeries of long and slender prismatic denticles of dentine, which are cemented together by their ossified capsules, this columnar denticle slightly decreasing in diameter, and occasionally bifurcating as they approach the grinding surface of the tooth."

The drawing represents a transverse section from the thickest part of a molar, and meeting the above description, displays, in the separating lines, the columnar denticles; in the centre, the pulp cavity, and in the intervening spaces the radiating dentinal tubules, the whole showing a curious example of a number of elementary teeth locked together, in fact, a compound tooth built of many into one uniform mass. An interesting and singular example of a similar disposition of parts may be seen in a horizontal section of the incisor of a lemur, with the difference that a space exists between each denticle; although a combined tooth, they stand out alone, as free processes from the base to the crown, without adhesion; consequently a transverse section cuts them into separate and distinct pieces, each (as regards structure) a tooth in itself.

Sections of teeth should be prepared and mounted to meet every possible appliance for illumination. Crouch End.

LEAVES FROM MY NOTE-BOOK FOR 1884. By A. KINGSTON.

THE

[Continued from p. 131.]

HE most notable circumstance during the month of May was the remarkable contrast between the severe frost at the latter end of April, and the summer heat which prevailed as early as from the 9th to the 12th of May. On the latter day the thermometer registered 80 degrees in the shade, while a correspondent from Doncaster gave a record for that day of 112 degrees in the sun, and it was certainly considerably upwards of 100 degrees in the sun, in many other places about mid-day on the 12th.

Few things in the botanical world were more remarkable, in the phenomenally dry summer of 1884, than the superabundance of the common red poppy (Papaver Rhaas), which brightened up many a broad stretch of cornfield with its ruddy glow, and in many cases outshining the green corn and producing a heavy crop of itself, which afforded employment to a number of young people and casual hands in collecting the flowers for use in drug distilleries.

From scarlet poppies to bats may seem a far cry, but, on a summer's evening at least, it need only be a question of looking up or down, so far as one of these curious "flying animals" is concerned. Early

in the evening on July 18th, in the broad daylight, and some little time before sunset, the writer's attention was attracted by what, at a distance, appeared to be a number of swallows hawking vigorously for insects in the neighbourhood of a group of trees. On getting nearer to them they were found to be bats, from 12 to 20 in number, of the great bat (Scotophilus noctula). I am aware that there was nothing very extraordinary in the number seen together of a bat which is known to be remarkably gregarious, especially in its winter quarters. Indeed, it is I believe on record, that the large number of 185 were taken from beneath the eaves of Queen's College, Cambridge, in one night, and 63 the following night. I have included the reference to it in these notes as a confirmation of the curious fact, that this particular species of cheiroptera, which has been singled out from about fifteen species to receive the distinctive name Noctula, is remarkable for the very opposite peculiarity of coming out by daylight, and earlier in the evening than any other species!

It would have been singular indeed, if such an exceptionally hot and dry summer had not produced some effect in that universe of "scales, legs, and wings, and beautiful things' " which make up the interesting domain of entomology. But passing over the unusual abundance of the common house-fly and the earwig, my notes refer chiefly to the lepidoptera. A passing notice must however also suffice for the exceptional numbers of the pretty orange-tip butterfly (Anthocaris cardamines), the variously coloured species of the Satyridæ, and the "blues," such as the charming little Polyommatus Adonis, to make room for a fuller reference to the fortunes of the better known Pieris brassica, or large white butterfly. In the autumn of 1883, the caterpillar of this butterfly was so abundant, that if this could have been conclusive evidence, horticulturists might have feared a direful visitation of white butterflies in 1884. But "there's many a slip," &c., even in butterfly economy. Probably owing to the absence of that peculiarly succulent condition of the cabbage tribe, which is so essential to this caterpillar's comfort, the larva of the large white butterfly was as remarkable for its absence last autumn as it had been for its abundance the previous year. In 1883, at one particular spot where the writer has been accustomed to watch their interesting transformations, about a score of caterpillars of this butterfly took up their positions and strapped themselves up to await the coming spring. But last autumn only one caterpillar was seen there, and the busy little ichneumon made short work of that one. Yet the conditions were just the same as to plants of the cabbage tribe within a similar distance. I mention the latter point as having some bearing upon the interesting question of butterfly instinct. It is perhaps too often assumed that the butterfly, having deposited its eggs on some object suitable for the food of its caterpillar, has

accomplished the purpose of its existence; and so it has, but may there not have been a previous element in the case? Even casual observers must have noticed that the further you get away from the homes and haunts of men, the more scarce becomes the white butterfly, while with many of the brightly coloured species the reverse is the case. This, prima facie, is of course only equivalent to saying that one finds the most suitable food for its larvæ in the garden, and the others in the fields and lanes, but the following incident will, I think, carry the point a little further. The most notable instance of the destructive operations of the caterpillar of the large white butterfly, which came under the writer's notice in 1883, was near a railway station on the Great Northern Railway, where a bed of plants of the brassica tribe (I think cauliflower) was completely denuded of every vestige of leaf, leaving nothing but the bare fibre and stalk of the plants. Two or three yards from the end of this cabbage bed, was a newlyerected waiting-room, constructed of wood from ground to roof. Up this structure the tribes of caterpillars went from the cauliflower bed in such numbers as to occupy every board in the roof! Forty or fifty yards away from this spot, but with no suitable hibernating quarters for the caterpillars to pass into the chrysalis state in, were similar cabbagebeds, but in this case the injury caused by the caterpillars was mild in comparison with the havoc wrought on the plants near the waiting-room. Was this predilection for the plants near the structure merely a coincidence? Or was it a recognition on the part of the butterflies, that the spot would afford the best chance of the caterpillars passing the chrysalis state in peace and comfort? Had the butterflies no interest in their progeny beyond providing them with proper feeding ground in the larva state, or did their instinct lead them to select a feeding-ground for one stage of their progeny near a suitable accommodation for the succeeding, or chrysalis stage? The point is one which might be of some interest in market gardening districts, or where cabbages, &c., are planted in open situations. To this note on butterflies I may add that, in August last, I put a specimen of the peacock (Vanessa Io) into a laurel bottle in which the leaves, though not very fresh, were sufficiently strong to at once stupefy the insect. When the time came for getting the specimen on to the setting-board I had quite forgotten my prisoner, and, being away from home for some time afterwards, I thought no more of the butterfly for more than a fortnight afterwards. On opening the bottle and taking out the butterfly, it flew across the room on to a table, and after a few exertions akin to a gasp (audible), apparently on account of the sudden change of atmosphere, it flew away in vigorous style over the neighbouring houses as if nothing had happened to it! I do not mention this as evidence against the use of the laurel bottle, because very

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much depends, of course, upon the frequency with which the laurel leaves are changed; but it shows how little the butterfly needs in the way of sustenance, in this the perfect stage of its existence, and how easily it can adapt itself to a different kind of atmosphere.

Reverting once more to ornithological subjects, the season of 1884 was somewhat remarkable for the free breeding of our fine old British bird the kingfisher, a circumstance probably due to the absence of floods; at any rate, taxidermists have rarely had such a harvest of kingfisher customers. When King James I. had a hunting box and stables (still in existence) in that neighbourhood for indulging his hunting proclivities, it is on record that his majesty frequently resorted to Royston, especially "at y season for shooting of dotterails, a sort of bird very common in these parts." I am afraid if his majesty could visit "these parts" now he would find the dotterell (Charadrius Morinellus) almost unknown; for it has now become very rare, and during the past year, as far as I can learn, has not been seen in its old haunts.

The welcome rainfall in September, with the warm weather which followed, produced after such an exceptional period of drought, some very curious manifestations in the vegetable kingdom, and led to not a few "strawberry" paragraphs in the newspapers, chronicling the abnormal appearance of ripe strawberries and apple blossoms at Michaelmas. The most singular instance of this kind which came under the writer's notice was a horse chestnut tree standing in the Hitchen market place, and which, though then divested of nearly every leaf, had quite a number of fine spikes of bloom upon it on October 21st. The large white butterfly was on the wing until about October 25th; the peacock and small tortoiseshell to the last day of the month, and the hardy passionflower (Passiflora cærulea) bloomed in the open air until the same date. About thirty species of wild flowers were in bloom up to the middle of November.

One incident, as a curiosity of natural history, may perhaps form a fitting close to the above record of odd fragments. It is not often that in the chapter of oddities among inferior living creatures, one comes across an incident embodying such an apparent sense of the ludicrous, or so much of the elements of a smart practical joke, as in the following case of insulting a scarecrow. The incident was narrated to the writer by Mr. Norman, the naturalist whose name I have mentioned above. Finding it necessary to put up something as a scarecrow, for the protection of a particular crop in his garden, he fastened up in a tree a dilapidated specimen of a stuffed fox. Exposure soon resulted in poor Reynard showing signs of decay; but imagine the owner's astonishment at the end of the summer, on finding that an impudent pair of flycatchers had actually built their nest inside the scarecrow, and brought up their brood of young ones there!

thing by classical writers of the olden times being Barometz, by which the fern is sometimes still called. Two tree-ferns are common: Alsophila podophylla, Hk., not nearly so finely cut as Cibotium and distinguished by the raised globular sori and rough scaly stem, and Brainea insignis, Hk., a smaller plant bearing the fructification closely packed on arched veins near the midrib. They are both pretty generally distributed throughout the island. We notice in the last place one of the prettiest and commonest of the ferns of Hong-Kong.

Fig. 146.-Dicksonia Barometz, Link. (Cibotium glaucum, Hk.)

Fig. 148.-Davallia tenuifolia, Sw.

frond, and situated at the margin and in the sinus of the lobe.

Cibotium glaucum, Hk., is a large handsome graceful fern, the much-cut fronds and glaucous or white powdery hue on the under-side easily serving to distinguish the species. It may be met with in every ravine, varying in height from 1-10 feet, although never attaining to the dimensions of a tree. The rhizome-that portion of the rachis which runs along the ground, and is neither root nor stem-is covered with short golden hairs, and is occasionally to be found above the ground in quaint, curious forms which have been taken to represent animals. These portions of the root are sometimes to be seen hawked about the streets of Hong-Kong and called "Lamb-Fern"-the name employed for the same

Gen. XIV. DAVALLIA, Sm. Hares' foot fern-it has been called in conservatories at home where one species is very often to be seen. In many houses here the root (or rhizome, properly speaking) is trained into the shape of balls and rings, and the fern is hung up as an ornament in verandahs.

The common species is Davallia tenuifolia, Sw. The frond grows from 1 to 8 inches high, is a bright light green and shiny. The tiny divisions are much cut and wider at the top than at the base. The sorus terminates the margin of the lobe. There is no mistaking this pretty little fern. It may be found everywhere. When growing by the sea in clefts of the rock, or on granite shelves at Kowloon,