THE LEMTJEID^. 459 



face, outside tlie front margin of tlie orbit. The frontal and 

 the jvigal bones are united behind the orbit, but a mere 

 bar of bone results from their union ; and it is so narrow 

 that the ojbit and the temporal fossa are in free com- 

 munication. The bony palate is elongated and, in many 

 species, its posterior free edge is thickened. 



The lateral processes of the atlas are, usually, expanded. 

 The lumbar region of the spine is elongated ; the vertebrsB 

 composing it, in some cases, being as many as nine. There are 

 nine bones in the carpiis. The ilia are narrow and elongated, 

 and the ischia are not everted. In most Lemurs, the tarsal 

 bones resemble those of the other Primates; but, in Otolicmis 

 and Tarsius, they have undergone a modification, a parallel 

 to which is not to be foimd among Mammals, but must 

 be sought among the Bcdrachia. When the distance be- 

 tween the heel and the digits is great in other Mammalia, 

 the elongation affects the metatarsal bones and not the 

 tars LIS; but, in these Lemurs, the calcaneum and the navi- 

 eulare are prolonged, as they are in the Frogs. 



The sublingua, a process of the mucous membrane of the 

 floor of the mouth, developed between the apex of the 

 tongue and the symphysis of the mandible, acquires a 

 considerable size, and is often denticulated, or comblike, at 

 its free end. The stomach is simple, with the cardiac and 

 pyloric apertm-es approximated. The coecum is long, and 

 has no vermiform appendage. 



In many Lemurs (Stenops, Nycticebus, Perodicticus, Arcto- 

 cebus, Tarsius) the great arteries and veins of the limbs 

 break up into retia mirdbilia formed of parallel branches. 



The ventricles of the larynx may be enlarged, but there 

 are no great air sacs, such as exist in many other Primates. 



In the brain, the cerebral hemispheres are relatively small 

 and flattened, and have narrow and pointed frontal lobes. 

 They are so short as to leave the cerebellum largely un- 

 covered. The gyi'i and sulci are scanty, or absent, upon the 

 outer surface of the hemispheres, but the internal face 

 exhibits the calcaiine sulcus. The large olfactory lobes 

 project forwards beyond the cerebral hemispheres. 



