858 ROBERT COLLETT, 



Leugth of tlie dental series in the upper jaw 31 mm, in the lo- 

 wer jaw 28 mm. 



In D. hallucatus the teeth are (comparatively) weaker and the 

 dental series shorter, than in the other species. 



Thus, although the young specimen of D. geoffroyi (A) has even 

 a shorter lower jaw (49 mm) than the fullgrown specimen of B. hallu- 

 catus (50 mm), the dental series is considerably longer (in the upper 

 jaw o5 mm, in the lower jaw 33 mm) than in the latter (31—28 mm), 

 although the teeth in this are less closely arranged than in D. geoffroyi. 



This great dissimilarity in the dental series of the two skulls, 

 which are about equal in size, is due to the much coarser and stronger 

 teeth of B. geoffroyi. 



While thus the lower m '^, in B. geoffroy% extends 6 mm beyond 

 the margin of the jaw which in the young individual is more than the 

 height of the lower jaw itself^), the corresponding tooth in B. hallucatus 

 has a height of scarcely 4 mm, whilst the height of the lower jaw below 

 the teeth is 6 mm. The incisors in the same jaw are in like manner 

 more slender in B. hallucatus., than in the other species, where they 

 attain to almost double the breadth. In the upper jaw the same 

 difference exists, although in both species the teeth are (comparatively) 

 shorter, and also somewhat more worn in B. hallucatus. 



The teeth, The dentition is, as in the other species: 



i h c h P h^ T (42). 



The Upper i ^ are longer than the other , more isolated , and 

 directed obliquely forwards, with their points somewhat convergiog, 

 without, however, touching each other. 



B. viverrinus (Shaw) 1800 (D. maugaei Geoffr. 1804) appears in 

 the formation of its teeth to agree exactly with B. geoffroyi. One 

 cranium of a very young individual which is preserved in the Museum 

 at Christiania, has the length of the lower jaw 50 mm; the dental 

 series in the upper jaw is 36 mm, in the lower jaw 33 mm. 



It is therefore seen, that of all these species, B. hallucatus has 

 the weakest teeth. And, as the fully developed skull with its high 

 crests etc. is of the same size as the quite young skulls of B. viver- 

 rinus and B. geoffroyi^ where the different bones are still most loo- 

 sely connected, and only the first traces exist of the crests, it is clear, 

 that B. hallucatus does not attain the size of the other species. 



1) In the older specimen the corresponding tooth is also G mm, but 

 the jaw has a height of 9 mm. 



