260 



PROF. HUXLEY ON THE CRANIAL AND 



[Apr, 6, 



The patterns of the crowus of the upper cheek-teeth (fig. 13, B) 

 are completely canine. The anterior inner cusp of the fourth upper 

 praemolar is very thick and prominent, and gives the crown of the 

 tootii the form of an almost equilateral triaugle. There is a well- 

 developed secondary cusp at the anterior end of the base of the 

 principal cusp of this tooth, so that, viewed from the outside, it 

 appears tricuspidate ; and sometimes there is a minute cusp behind 



Fig. 13. 



B 



K 



ifsNat'.^ize.. ^MaiiSize. 



A, lower, and B, upper cheek -teeth' of Otocyon lalandii ; the last molar iu the 

 upper jaw is absent; C, the lower sectorial tooth of Otocyon from the inner 

 side, of twice the natural size ; D, the correspondiug tootli of C. :cnla, and 

 E, of C. I)q}it:% reduced to the same absolute length and also viewed from 

 the inner side ; a. p. anterior external cusp; (r.i. anterior internal cusp; 

 a b. cusp-line. The tooth of the Fennec is obviously intermediate in 

 character between that of Otocyon and that of the Wolf The comparison 

 of these figures with figs. 6 and 7 will give a very good conception of the 

 e.Ktent and the nature of the modifications of the cheek-teeth in the Canidse. 



the principal inner cusp. In both points this tooth approaches the 

 upper sectorial of Nasua. The crowns of the molars are broader 

 than they are long; but the difference is less than iu most Canidse. 

 Their four cusps, with the cingidura on the inner side, are very 

 distinct ; and the second upper molar is much larger in proportion 

 to the first than in other CanidiB. 



In the mandible, the third prgemolar has a sharp cusp at the anterior 

 end of its base; the first molar has the inner cusps higher than the 

 outer ones ; and the anterior paired cusj)s are set iu a nearly trans- 

 verse line, the inner hiding the outer when the tooth is viewed from 

 ■within (fig. 13, C). In both these respects the crown of this tooth 



