46 



THE MAMMALIAN ORDER PRIMATES 



[sect, a 



Stomach 



Liver. 



Digits : of fore and hind limbs bear flat nails except the second 

 digit of the hind limb, which bears a claw. Both pollex and 

 hallux are opposable. 



Orbit : surrounded by a bony ring. (Cf. Fig. 18.) 



Lachrymal foramen : external to orbit. 



Hyoid bone : anterior larger than posterior cornu. 



Colon : " bent on a bight" in its transverse portion. (Cf. Fig. 19.) 



Cerebral hemi- 



spheres : feebly convo- 

 luted and not prolonged 

 far backwards over cere- 

 bellum (Fig. 44) : rhin- 

 encephalon relatively 

 well-developed. 



Mammae : two in 

 number, thoracic in po- 

 sition; they may be 

 supplemented by an 

 abdominal pair. 



Uterus: bi-cornuate. 



Placenta : diffuse. 



The Sub-order Le- 

 muroidea comprises the 

 true Lemurs (Family 

 Lemuridae), so called 

 from their ghost-like 

 appearance at night. 

 Geographically, their 

 distribution is almost 

 entirely confined to the 

 island of Madagascar, 

 in which they have found congenial surroundings ; and of the 

 local fauna they are very characteristic. A few examples occur in 

 Africa and Asia. Fossil representatives occur, not in Madagascar 

 only, but also in Europe and in North America. 



The arboreal animal known as the Aye- Aye, Cheiromys or 

 Daubentonia madagascariensis is, as its name indicates, a Malagasy 

 representative. It is so peculiar as to have been assigned to a 



Caecum 



Fig. 19. Part of the alimentary canal of a 

 Lemur: note the curiously contorted colon, and 

 the enormous appendix caeci. 



