﻿76 PLEISTOCENE MAMMALIA. 



of Premolar 4. The tubercular portion is supported by a normal cylindrical fang in its 

 proper position. It is thus seen that in this tooth all the essential parts of the per- 

 manent upper carnassial are represented, but they are so modified in form as to cause 

 the tooth to fulfil the functions of a tubercular molar. 



§ 3 j3. Milk dentition of the lower jaw. (PL XIII, figs. 3, 4, 7.) — The third milk 

 incisor, which we have represented in fig. 3, is the only one which has come before our 

 notice ; it is from Bleadon cave, and is introduced in this figure for the reason assigned 

 above, in our account of the milk molar 2 of the upper jaw. The tooth differs 

 from the permanent incisor, by possessing not only the posterior cusp (c), but also the 

 anterior (5), on each side of the low, blunt, slightly recurved cone (a). The three cusps 

 are traversed by a slight blunt edge, and the crown is larger than the fang, which is, as 

 far as can be seen, subcylindrical, slightly compressed, and recurved. Of the remaining 

 milk incisors, we know nothing but the fangs ; they appear to be more equal in size to 

 incisor 3 than in the adult animal. 



The deciduous canine DC of the spelaean lower jaw (figs. 3, 4, and 7), is of so 

 remarkable a form, that it can hardly be confounded with that of any other animal. The 

 crown (a) is compressed parallel to the median line, short and recurved, without grooves 

 on the external aspect ; the flattened internal area is well defined posteriorly by the tren- 

 chant edge, anteriorly it is separated from the external surface by another ridge, passing 

 from the tip of the crown downwards to the point where a small buttress or cusp of 

 enamel (b) occupies the inner base, and gives the crown almost the appearance of a flat- 

 tened upper permanent incisor three. The fang is very broad antero-posteriorly, and 

 deeply indented on the inner surface to make way for the germ of the permanent canine. 

 DM3 (figs. 3, 4) is separated from the canine by a diastema, increasing with age. It 

 consists of a stout, primary cone (a) inclined slightly backwards, with the secondary sub- 

 equal cusps (b) and (c). The cingulum is well developed, and forms a well-marked but 

 blunt cusp on the intero-anterior border of (b), and a very distinct and sharp-edged 

 accessory cusp (e) posterior to (c). The whole tooth is traversed from the summit of (b) 

 to (<?) by a sharp trenchant ridge, the cusps being divided from each other by clefts. 

 The cone (a) is smaller than its homologue in Hycena spelaa. There is occasionally a 

 supplementary, minute cusp on the internal side of (c). The tooth is supported by two 

 strong, cylindrical, divaricate fangs. 



The sectorial DM4 consists of two blades, the posterior (a) and the anterior (3), and 

 a small secondary (c), posterior to which the cingulum folds into the posterior acces- 

 sory (<?), which, however, is frequently obsolete. The cone (a) is higher than (5), and is 

 inclined backwards, but less so than in MI, which in other respects the tooth very closely 

 resembles, both in form and in the scissor-like function that it performs with DM3 , by 

 which it is overlapped. A trenchant edge passes from the summit of (<$) backwards to 

 the posterior base of the tooth, the divisions of all the cusps being strongly marked by 



