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 Chiromys, 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 seaphoid 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 Mesopithecus and 
of Tarsius, the actual hard and fast lines between a// 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 
1 For a general account of the Primates, see Forbes in Allen's Naturalists’ 
Library, London, 1894. 
