CHAPTER XVII 



PRIMATES 



Order XIII. PRIMATES. 



The highest of mammals, the Primates/ may be thus differ- 

 entiated from other groups : — Completely hairy, generally arboreal 

 mammals, with five digits on fore- and hind-limbs, provided with 

 flat nails (except in the case of certain Lemurs and the Marmosets), 

 the phalanges that bear these being flattened at the extremity and 

 expanded rather than diminished in size. The fore-feet are grasp- 

 ing hands as a rule, and the hind-feet walking as well as (generally) 

 grasping organs, and the mode of progression is plantigrade. The 

 teats, except in Cliiromys, are thoracic, and even axillary in 

 position. The skull is characterised by the fact that the orbital 

 and the temporal vacuities are, at least partly, separated by bone. 

 The clavicles are always present. The carpus has separate lunar 

 and scaphoid bones, and the centrale is often present. There is 

 rarely an entepicondylar foramen in the humerus, except in some 

 archaic Lemurs. The femur has no third trochanter. The stomach 

 is usually simple, being sacculated only in Semnopithecinae. The 

 caecum is always present, and often large. 



This great group could be easily divided into two separate 

 orders, the Apes and the Lemurs, if it were not for certain fossil 

 types. As will be seen from the description of Nesopitliecus and 

 of Tiirsius, the actual hard and fast lines between all Apes and all 

 Lemurs are very few. On the other hand, it is a little difficult to 

 draw a hard and fast line between the Primates as a whole — or 

 at least between the Lemurine section — and the Creodonta, a 



^ For a general account of the Primates, see Forbes in Allen's Naturalists' 

 Library, London, 1894. 



