406 MAMMALIA. 



one inner cusp. The lower molars are antero-posteriorly elongated, and 

 the hindermost is extended into a prominent posterior talon ; these and 

 premolar 4 much resemble the corresponding lower teeth of Adapis. The 

 typical skull of Megaladapis madagascariensis measures about O25 m. in 

 length. 



Nesopithecus. A remarkable large extinct lemur from Madagascar 

 known only by parts of the skull and dentition. The facial profile of the 

 skull is remarkably steep and the orbits are directed forwards. The 

 orbital cavity must clearly have opened into the temporal fossa behind, 

 and the lachrymal foramen is situated just upon its anterior rim. The 



, , , ,. , . i. 2, c. 1, pm. 3, m. 3 , 



dental formula is . r 2 r^ -^ . The upper incisors are implanted 



i. 1, c. 1, pm. 3, m. 3 



obliquely and those of the middle pair are much enlarged, while the outer 

 pair are comparatively small. The upper canine is stout, with a well- 

 developed basal cingulum. The upper premolars exhibit an internal 

 cingulum, and pm. 2, 3 are antero-posteriorly elongated, while pm. 4 is 

 longest in a transverse direction. The upper molars are quadrate in 

 shape, diminishing in size backwards ; and each bears four tubercles, the 

 outer and inner pairs being opposite and connected by transverse ridges. 

 The rami of the mandible are fused at the symphysis and the small front 

 teeth, which seem to be of uniform size, project forwards, having a very 

 oblique insertion. These probably represent one pair of incisors and a 

 flanking pair of canines. The first of the three lower premolars, namely 

 pm. 2, is enlarged and shaped to undertake the function of a canine a 

 feature common among existing lemurs. The three lower true molars are 

 quadrate in shape, like those of the upper jaw, and diminish in size back- 

 wards. The hindermost lower molar is destitute of a posterior talon. 

 The typical and only known species is Nesopithecus roberti, founded upon 

 the facial and palatal part of a cranium from a swamp at Sirabe, Central 

 Madagascar. The length of the upper dental series, from the canine to 

 the hindermost molar inclusive, is 0'05 m. 



Sub-Order 2. Anthropoidea. 



The true apes, with the orbital cavity completely separated 

 by a bony partition from the temporal fossa, appear first, so far 

 as known, in the Middle Miocene of Europe; but all the remains 

 hitherto discovered seem to represent forms closely related to 

 the genera still surviving in the warmer regions of the Old 

 World. 



Most of the European fossils appear to be referable to the 

 family of Cercopithecidae, which includes all the living Old 

 World apes except the gibbons, orangs, chimpanzees, and 

 gorillas (Simiidae). The oldest fragments are jaws and teeth 



