THE LEMURIDjE. 389 



All the JLemuriddB are habitually quadripedal, have the 

 integument furry, and are usually provided with long tails 

 which are never prehensile. They are devoid of cheek- 

 pouches and of callous patclies upon the integument covering 

 the ischia. 



The fore-limbs are shorter than the hind-limbs. In the 

 foot, the hallux is large and opposable, and the second digit 

 differs from the rest in size, and in the claw-like form of its 

 nail. The fourth digit is usually longer than the others, the 

 difference being especially marked in the pes. 



In the skull, the brain-case is small relatively to the face, 

 and is contracted anteriorly. If a straight line drawn from 

 a point midway between the occipital condyles, through the 

 median plane of the skull, to the junction of the ethmoid and 

 presphenoid, in the floor of the cerebral cavity, be termed the 

 basi-cranial axis ; and if the planes of the cribriform plate of 

 the ethmoid, of the tentorium cerebelli, and of the occipital 

 foramen, be respectively termed the ethmoidal, tentorial, and 

 occipital planes; then, the greatest length of the cerebral 

 cavity hardly exceeds the length of the basi-cranial axis ; and 

 the ethmoidal, tentorial, and occipital planes are very much 

 inclined to that axis. The upper aperture of the lachrymal 

 foramen lies upon the face, outside the front margin of the or- 

 bit. The frontal and the jugal bones are united behind the or- 

 bit, but a mere bar of bone results from their union ; and it is 

 so narrow that the orbit and the temporal fossa are in free 

 communication. 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 vertebrae 

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

 are nine bones in the carpus. The ilia are narrow and elon- 

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

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

 Otolicniis and Tarsius, they have undergone a modification, a 

 parallel towhich is not to be found among Mammals, but must 

 be sought among the Batrachia. When the distance between 

 the heel and the digits is great in other Mammalia, the elon- 

 gation affects the matatarsal bones and not the tarsus ; but, in 

 these Lemurs, the calcaneum and the naviculare 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 



