656 



PRIMATES. 



the last molar in both jaws is smaller than the preceding molar. 

 In many of them the tail is prehensile. 



In the Catarrhina the internasal septum is narrow, there 

 is a bony external auditory meatus, the frontal usually meets 

 the squamosal in the side wall of the skull (not in Simia), and 

 the jugal does not join the parietal. The tail is never pre- 

 hensile. 



The Cebidae are found fossil in the Eocene. The other 

 families, including the Anthropomorphidae, are first found in 

 the Miocene. 



Fam. 1. Hapalidae. Marmosets. Dentition i f c \ p f m | - ; 

 upper molars tritubercular, the inner cusp 

 being V-shaped ; upper premolars broader 

 than long with pointed inner and outer 

 cusp ; lower molars with four cusps, m 2 is 

 the largest in both jaws ; canines project- 

 ing. The skull is rounded and the brain 

 case capacious. The fore-limbs are shorter 

 than the hind-limbs. All the digits have 

 claws except the very small hallux, which 

 has a nail, and the pollex is not opposable. 

 The tail is longer than the rest of the body 

 and is not prehensile. Cheek pouches and 

 ischial callosities are absent ; the ears are 

 large and hairy. The cerebrum is large and 

 has a smooth surface ; there is a posterior 

 cornu, a hippocampus minor and a deep cal- 

 carine fissure. There are no cheek pouches. 

 They are frugivorous and insectivorous, and 

 arboreal ; and they give birth to three 



young at a time. They are confined to the Neotropical Region. Hapale 

 111., the lower canines are approximated to the incisors and do not exceed 

 them in length ; about 7 species. Midas Geoff r., lower canines longer 

 than incisors, about 24 sp. 



Fam. 2. Cebidae. These are also habitually quadripedal, but the 

 thumb is opposable as well as the hallux and the manus is a hand. All 

 the digits of both limbs have nails. Dentition ifcyjofmf; upper 

 and lower molars tetracuspidate, premolars bicuspidate. The brain 

 case is rounded and smooth ; there is no mastoid process and the styloid 

 process is not ossified. The skull varies considerably in the length of 

 the face and the position of the foramen magnum. In Mycetes which 

 represents one extreme the face is prominent and the plane of the fora- 

 men magnum posterior and almost vertical. In Chrysothrix, at the other 

 extreme, the face is less prominent, the brain case arched, and the foramen 

 magnum is on the under side of the skull, near its middle. There is a 

 centrale in the carpus ; the pollex is reduced to its metacarpal in Aides. 

 The tail is almost always long and prehensile ; the ears are rounded and 

 bare ; cheek pouches and ischial callosities are absent. The stomach is 

 simple, the caecum large, without vermiform appendix. The brain is 



FlG. 330. Skull of Pitkecia sata- 

 nas (from Claus). 



