The deciduous teeth consist of :—i. 0 3 , 1 1 3-3 m. = 28. The figure of the of the young Hyena crocuta in the posthumous edition of the " Ossemens Fos siles," 8vo. 1836, pl. 190, fig. 3, shows that stage when the correspondence with the formula of the genus Felts is completed by the appearance, in the upper jaw, of a small pre molar in the interspace between the canine and first molar of the deciduous series : but this appearance is due to the apex of the first permanent premolar which cuts the gum before any of the normal deciduous teeth are shed : whether it is preceded, as in the dog, by a deciduous germ-tooth in the foetus, I know not. The first normal deciduous molar is two-fanged, and has a more compressed and consequently more carnivorous crown than that of the second permanent premolar by which it is succeeded. The second deci duous molar is the sectorial tooth : the inner tubercle is continued from the base of the middle lobe, and thus resembles the permanent sectorial of the Glutton (Gulo) and many other Match& ; the deciduous tubercular molar is relatively larger than in the adult Hyerna, and offers another feature of resem blance to the permanent dentition of the Glutton. It is also worthy of remark that the exterior incisor of the upper jaw is not only absolutely, but relatively smaller in the immature than in the adult dentition of the hyaena, and again illustrates the resemblance to the more common type of dentition in the Carnivora.
The first and second deciduous molars be low have more compressed conical crowns than their successors : the third deciduous molar is the sectorial tooth, and, again, as in Cul°, has a better developed hinder tu bercle than the permanent sectorial ; it is not displaced by this tooth, but, as in other Car nivora, by a premolar of more simple cha racter. The permanent sectorial is deve loped posteriorly, and rises, like other true molars, without displacing a deciduous pre decessor.
The permanent dentition of the II.yeena, as of other genera or families of the Carnivora, assumes those characteristics which adapt it for the peculiar food and habits of the adult, and mark the deviation from the common type, which always accompanies the progress to maturity. The most characteristic modifi cation of this dentition is the great size and strength of the molars as compared with the canines, and more especially the thick and strong conical crowns of the second and third premolars in both jaws, the base of the cone being belted by a strong ridge which defends the subjacent gum.* This form of tooth is especially adapted for gnawing and breaking bones, and the whole cranium has its shape modified by the enormous development of the muscles which work the jaws and teeth in this operation.t Adapted to obtain its food from the coarser parts of animals which are left by the nobler beasts of prey, the hyaena chiefly seeks the dead carcass, and bears the same relation to the lion which the vulture does to the eagle. In consequence of the quantity of bones which enter into its food, the excrements consist of solid balls of a yellowish white colour, and of a compact earthy fracture. Such specimens of the sub
stance, known in the old Materia Medica by the name of " album graecum," were dis covered by Dr. Buckland in the celebrated ossiferous cavern at Kirkdale. They were recognised at first sight by the keeper of a menagerie, to whom they were shown, as resembling both in form and appearance the faeces of the spotted Hymna; and, being analysed by Dr. Wollaston, were found to be composed of the ingredients that might be expected in faecal matter derived from bones, viz. phosphate of lime, carbonate of lime, and a very small proportion of the triple phosphate of ammonia and magnesia. This discovery of the coprolites of the hymna formed, perhaps, the strongest of the links in that chain of evidence by which Dr. Buckland proved that the cave at Kirkdale, in York shire, had been, during a long succession of years, inhabited as a den by hyaenas, and that they dragged into its recesses the other animal bodies, whose remains, splintered and bearing marks of the teeth of the hymna, were found mixed indiscriminately with their own.
The dentition of the Weasel tribe (Muste Mee) is illustrated (in M. 580, IV.) by that of the Otter, Mustela Lutra of Linnmus, and which is essentially a great aquatic Weasel or 3-3 1-1 Polecat; its dental formula is i, — c.
3 —3' 1-1' 4--41 : = 36. In the Martin cats p.
3-3' —1 (Mustela mantes, L.), the little homotype of p. 1 above is present in the lower jaw ; in the bloodthirsty stoats and weasels, p.1 is absent in both jaws ; as it is likewise in the great sea otter (Enhydra), in which also the two middle incisors are wanting in the lower jaw. In this animal the second premolar (p. 3) has a strong obtuse conical crown, double the size of that of p. 2 ; the third premolar (2). 4) is more than twice the size of p, 3, and represents the upper carnassial or sectorial strangely modi. fled; the two lobes of the blade being hemi spheric tubercles. The last tooth, az. 1, has, a larger crown than the sectorial, and is of a similar broad crushing form. In the lower jaw the molar series are not separated by any interspace: the first and second premolars have oblique obtuse conical crowns. The third premolar (p. 4) is more than twice the size of the second (p. 3) and supports a large anterior hemispheric protuberance with a small internal tubercle and a posterior basal ridge. The first true molar has an oblong quadrate crown with an anterior small tubercle, a larger and more prominent inner one, and the rest of the broad horizontal surface un. dulating. The second true molar has a trans.. versely elliptical crown depressed in the centre. When the teeth are in apposition, the anterior third of the first true molar below is applied to the inner tubercle of the last premolar above ; the rest of its crown plays upon that of its homotype, the first true molar in the upper jaw, leaving a small part of that tooth to receive the appulse of the second true molar below, which has no corresponding tooth in the upper jaw.