HIGH SCHOOL ZOOLOGY. 103 



In contrast to the inunobility of the dorsal region of the 

 vertebral colinnu is the great mobility of the cervical and caudal 

 regions. Two vertebrse support by their ribs the ilia, and are 

 consequently spoken of as sacral. With the exception of the 

 mandible and hyoidean apparatus, all the bones of the skull are 

 intimately united, the quadrate is firmly connected with the 

 others, and two bones (which do not occur in the Ichthyopsida), 

 the quadratojugal and the jugal, unite it to the maxilla. The 

 hyoidean apparatus is interesting because it has undergone the 

 reduction which we would have anticipated in an animal where 

 there are no gills. The arches which persist serve for the origin 

 of the muscles of the tongue. 



3. As to the appendicular skeleton it has many points of 

 resemblance to that of the Menobranch, tlie hands and feet are 

 even more primitive, and the shoulder girdle resembles it in the 

 free termination of the coracoids, but the pelvic girdle is some- 

 what more complicated, presenting a large perforation between 

 the pubis and ischium on each side. 



4. The chief points in which the brain of the Snapper differs 

 from that of the Urodela is in the greater development of the 

 cerebral hemispheres and the cerebellum in contrast with the 

 other parts. 



5. In the intestinal canal the absence of teeth and the jjreat 

 length of the short intestine ai'e noteworthy, while that we have 

 to do with an air-breathing Vertebrate is sufficiently evident from 

 the large size of the lungs. In most air-breathing animals the 

 change of the air in the lungs is aided by respix-atory mo^■ements 

 of the thorax, but as the thorax here permits of no such move- 

 ments, this function is luidertaken by the thin wall of the body- 

 cavity in front of and behind the bridges which join the carar 

 pace and plastron. The circulatory system is also adapted to 

 the change of the method of breathing, for not only is the 

 blood returned from the iungs into a different* chamber from 



