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Show bristles in the Dassies (Procavia) is very important. Mr. Beddard states that these are the only ungulates in which he has found these bristles. Carpal callosities are, however, described by Dr. W. Leche1 as occurring in Wart-Hogs (Phcwochcerus); although they are stated by their describer to be acquired, and not primitive structures. Whether the latter statement is calculated to modify Mr. Beddard's opinion with regard to the nature of the carpal bristles in the Dassies, I am, of course, unable to say. Of special importance is the occurrence of bristles in these structures, since, even if hairs be found to exist on the callosities of foetal Equidce, this would be no bar to the supposition of their glandular nature. As regards the structure of the callosities themselves, it may be noted that in the Horse both pads are of a distinctly wai-ty nature, and that the hind pair are certainly in a more decadent condition than the other, being in fact on the verge of disappearing. In the Zebras, on the other hand (in which the hind one has been lost), the fore-callosity is larger and much less warty and also situated higher up. In dried skins it is, in fact, much more like the pale glandular patch of skin below the ear of a Reedbuck \ In this connection we have to bear in mind not only Mr. Beddard's observations alluded to above, but likewise others by Mr. Bland Sutton3, in which it is pointed out that in certain Lemurs decadent glands are actually converted into bunches of spines, which are practically almost the same as warts ; that is to say, they are hypertrophied growths of somewhat abnormal dermal tissue. Hence there seems no primd facie reason why the callosities of the Equidce should not be decadent glandular structures, the decadence being more marked in the two pairs of callosities of the Horse than in the single pair of the Asses and Zebras. There is, however, another point which may have an important bearing on the subject. From the presence of a depression in the skulls of Hipparion, Hippiclium, &c., it is evident that primitive Horses were furnished with face-glands comparable to those of Deer; such glands probably having a function somewhat analogous to ‘that of the scent-glands on the limbs of the latter. If, then, the existing Equidce have got rid of their face-glands, as being (perhaps on account of change of habit) useless, it is conceivable that, for the same reason, they may have also discarded their limb-glands. If these suppositions (and they are but suppositions) be well founded, it follows that a tarsal and a carpal gland must have existed in the common ancestors of the Horses and Deer ; that is to say, in the common stock of all modern Ungulates save the Elephants and perhaps the Dassies. And it may be urged that if this were the case, traces of such glands ought to be met with in Tapirs, Rhinoceroses, Pigs, Hippopotamus, &c. So far as I am 1 Biol. Centralblatt, vol. xxii. p. 79 (1902). 2 It would be important to examine the histological structure of .the callosity in a Zebra. 3 Proc. Zool. Soc. 1887, p. 369. *202 OX THE CALLOSITIES OX TIIE LIMBS OF THE EQUIDJ2. [Mar. 3, |