Fossil Monkeys from Madagascar. 



435 



incisors were strongly developed, the outer being much smaller. 

 The incisors being inserted obliquely, there is left a triangular gap 

 between them and the strong canine. This last is provided with an 

 internal basal cingulum, terminating in a small posterior cusp. The 

 two anterior premolars have their longest diameter parallel to the 

 long axis of the skull, whilst the third is longest in a transverse 

 direction. They overlap each other, the first two being inserted 

 obliquely in their alveoli. All of them are provided with an internal 

 cingulum. The three molars are each composed of four tubercles, 

 the outer and inner pairs being placed opposite one another and 

 connected together by transverse ridges. This is the pattern of the 

 Cercopithecidaj ; but, unlike the Old- World monkeys, the molars 

 decrease in size from before backwards. 



The left mandibular ramus of another specimen, with less 

 worn teeth, seems referable to the same species. The incisors 



<* 



Fig. 3.— Left mandibular ramus of another specimen of Nesopithecm Roberti. 



are wanting; but from the alveoli of both sides preserved, it is 

 seen that they were four in all, and inserted obliquely. The 

 remainder of the teeth of the left side are six in number : 

 three are molars, their patterns being after the type of those 

 in the upper jaw, and likewise decreasing in size from before 

 backwards; no talon to the last inferior molar. Situated between 

 the incisors and the molars are three teeth, viz. one less than 

 in the upper jaw ; and the question arises, whether the missing 

 tooth is the canine or one of the premolars. The anterior of the 

 three teeth in question is caniniform ; but, in adapting the lower 

 dental series to the upper one, it may be clearly seen that this 

 caniniform tooth occupied the place behind the upper canine; so 

 that, according to our received definitions, this tooth is not to be 

 considered a canine, but a premolar. At any rate, whilst the dental 

 formula of the upper teeth agrees with that of the Cebidae, it is 

 quite peculiar in the lower jaw; and whilst the pattern of the 

 molars is that of the Cercopithecidae, the premolars differ alike 

 from Old and New World monkeys. The two posterior lower 



