252 THE DENTAL SYSTEM OF THE PRIMATES [SECT. A 



TARSII. Tarsius spectrum. (Fig. 181.) 

 The long styloid upper median incisor is supplemented laterally by a very 

 diminutive lateral tooth ; no interval separates the upper median incisor 

 teeth (as in Lemurs). The mandibular teeth are remarkable for their 

 number, since there are but two, one on each side. They are not (as in 

 Lemurs) procumbent, and in their conical form, they suggest the dentition 

 of Insectivora. 



ANTHROPOIDEA. Cebidae. Cebus capucinus. Fig. 182. 



In the Cebidae the disparity in size between the upper and lower incisor 

 teeth (as described in the Lemuridae) is not to be seen, but there is still 

 a slight tendency (quite distinct in Pithecia) to procumbency in the lower 

 incisors (cf. Fig. 21). 



The median teeth are provided with chisel-shaped crowns, the lateral with 

 conical crowns : the latter crowns when worn down by use quickly assume a 



i ) 



Fig. 180. Fig. 181. Fig. 182. Fig. 183. Fig. 184. 



Fig. 180. Incisor teeth of a Lemur. (No. 4, Mus. Zool. Cant.) 



Fig. 181. Incisor and lower canine teeth of Tarsius spectrum, x 2. (Mus. 

 Anat. Cant.) 



Fig. 182. Incisor teeth of Cebus capucinus. (No. 1093, Mus. Zool. Cant.) 



Fig. 183. Incisor teeth of a Macacus monkey. 



Fig. 184. Incisor teeth of Hylobates miilleri (ad. & W. L. H. D. priv. coll.) 



chiseblike edge, but in the unworn condition their form is as described above. 

 These remarks regarding the crowns of the teeth apply to the Cercopithecidae, 

 and to Hylobates, Simia, and Gorilla, but not to Anthropopithecus or to the 

 Hominidae. 



The combined upper series is wider than the lower set. Of the upper four 

 teeth, it is to be remarked that no median gap remains and that the outer 

 (lateral) teeth are smaller than the median pair, while the outer angle of the 

 crown is more open in the lateral than in the median teeth. Of the lower 

 teeth the lateral surpass the median pair in size. 



ANTHROPOIDEA. Cercopithecidae. Cercopithecus. Fig. 183. 



The lower incisor teeth are still less procumbent in the Cercopithecidae 

 (cf. Fig. 28); the upper median incisors, as in all the Anthropoidea, are in 

 contact and the upper median teeth much surpass the lateral teeth in size. 

 The median and lateral lower incisor teeth are nearly equal in bulk, the 

 lateral pair being rather stouter than the median. 



