698 



PRIMA TES 



the woodcut is of much larger dimensions. The skull of A. magna, 

 which measures upwards of 4 inches in length, resembles that of 

 A. parisiensis in its general characters, but is modified much in the 

 way that the skulls of larger animals differ from the smaller ones of 

 the same natural group. Thus the brain-chamber and orbits are 

 relatively smaller, the face larger, the muscular crests more 



developed, and the constriction be- 

 tween the cerebral and the facial 

 portion of the skull more marked. 

 These modifications remove the skull 

 in its general characters still farther 

 from the existing Lemurs — so much 

 so that M. Filhol refers it and the 

 other species of Adapts to a distinct 

 zoological type, intermediate between 

 the lemurs and the pachyderms, to 

 which he gives the name of Pachy- 

 researches do not support this view. As 



Fig. 333.— The left upper cheek-teeth 

 of Adapts magna, from the Upper Eocene 

 of Hampshire. 



lemwiens, but later 

 mentioned above, it has been suggested that Ccenopithecus lemuroides 

 is inseparable from Adapts parisiensis, but the postero- internal 

 column of the upper molars is said to be larger. The genera 

 Tomithcrium and Notharctm, of the Eocene of the United States, 

 appear to be allied to Adapis, but the second has a larger lower 

 canine. The same deposits have also yielded more or less imper- 

 fect remains of other forms departing more widely from the existing 

 Lemuroid type. Of these Hyopsodas, of the Wasatch and Bridger 

 Eocene of the United States, has the dental formula if, c i p 



4. 



4> 



'in :: 



The quadrituberculate upper molars have well -developed 

 accessory intermediate columns (protoconule and metaconule), and 

 thus resemble those of Microchcerus ; the external surfaces of the 

 outer columns of their teeth being flattened, with vertical ridges 

 and a distinct cingulum. The third upper molar has its postero- 

 internal column (hypocone) partly aborted, but is otherwise as well 

 developed as the preceding molars. Microsyops, of the North 

 American Eocene, appears to have been 

 an allied form in which there were prob- 

 ably only three premolars. 



The genera Protoadapis and Plcsiadapis, 

 from the lowest Eocene of Eheims, may 

 not improbably be regarded as primitive 

 Lemuroids. The lower molars are quin- 

 quetubercular, and not unlike those of 

 Mirrosyops ; the dental formula of the 



lower jaw is i 2, c 1, 

 first-named genus, but in 

 dentition is reduced to i 



p 3-4, 111 3 in the 

 the second the 



Fig. 334. — The right upper 

 cheek-teeth of Plcsiadapis remen- 

 sis; from the Lowest Eocene of 

 Rheims. X 3. p, 3, 4, premolars ; 

 m, 1, 2, 3, molars. (From Osborn.) 



ij c (T> P "fj m '■':• 



In Plesiadapis the lower 



