I2 ALLEN'S NATURALIST'S LIBRARY. 



for the upper jaw, and the sphenoidal fissure, which gives 

 exit to the third, fourth and sixth cranial nerves, have but 

 one aperture, as in the Rabbit, which belongs to the 

 Rodentia. 



The sacral vertebrae are generally three in number, and the 

 lumbar and dorsal together vary from nineteen to twenty-three. 



The brain, as Sir William Flower has observed, departs con- 

 siderably from the form of what may be called the primatial 

 type, and approaches in form to that of the carnivorous 

 animals. The hind-brain, or cerebellum, is not completely 

 covered by the cerebrum. The latter has but few convolu- 

 tions (indicating a low intelligence), but its posterior lobe is 

 always present, though more or less rudimentary, and so also 

 are many fissures, which are characteristic of its surface in 

 the higher Primates. The olfactory lobes are usually large and 

 not covered by the cerebrum. 



The uterus and structures for the nutrition of the young 

 prior to birth are low in type, and approximate to the condi- 

 tions seen in the Pig, the Horse, the Chevrotains, and the 

 Ruminants. The unborn Lemur is often encased (as among 

 the Sloths) in a skin-like covering (epitrichiwri) which breaks 

 into patches before birth. 



The tongue has a horny supplementary under-tongue (sub- 

 lingua) attached beneath it. The stomach is simple, not 

 formed of several compartments. The transverse portion of 

 the great intestine is convoluted in a remarkable manner upon 

 itself, the caecum also being very large. The main arteries of 

 the arm and leg break up (as in the Sloths) into an immense 

 number of small vessels (called retia mirabilia) parallel to one 

 another instead of being simple branching trunks. 



The long tendons of the muscles for flexing the digits (the 



