264 zoo loot. 



having the cerebral hemispheres small, smooth, with none 

 or few convolutions, in front not covering the olfactory 

 lobes, and behind leaving the cerebellum wholly or partly 

 uncovered. We now come to the Educabilia, in which the 

 brain is more highly developed, the cerebral hemispheres 

 being furrowed or convoluted, and partly or almost wholly 

 covering the cerebrum. We begin with two very aberrant 

 orders, the whales and Sirenians, in which the body is fish- 

 like, though the tail is horizontal; the pelvis and hind 

 limbs are wanting, either wholly, or minute rudiments 

 may be present; and they are aquatic, occasionally leaping 

 out of the water, but usually only showing the dorsal fin 

 or nose when at the surface to breathe. 



The whales and porpoises have a large, broad brain, with 

 numerous, complicated, and deep convolutions. 



In the skull the aperture for the spinal cord is entirely 

 posterior in situation and directed somewhat upward. The 

 lower jaw is straight. The teeth are conical, with a sin- 

 gle root, but are sometimes wanting. There is no neck; 

 the cervical vertebrae are sometimes confluent, forming a 

 single mass. The limbs form a pair of paddle-like append- 

 ages just behind and under the head, which are supported 

 by short, flattened limb-bones, the carpals and phalanges 

 often separated by cartilage; the second digit being com- 

 posed of more than three phalanges. There are two mam- 

 mae situated near the tail. The external nostrils are either 

 single or double, and are situated on the top of the head; 

 they are modified to form the spiracles or " blow-holes;" 

 certain folds of the skin prevent the water from entering 

 the air-passages. The vapor blown from the holes does 

 not consist of water, but of the mucus from the nostrils, 

 and the moisture in the breath. The blow-holes vary in 

 form in different kinds of whales. The " spout" or stream 

 of vapor issues in a single short stream from the extreme 

 end of the snout, and curls over in front of the head; that 

 of the fin-back whale forms a single column of vapor about 

 tern feet high; the right, humpback, and sulphur-bottom 



