MUSCULAR SYSTEM. 161 



fingers and toes, and the muscular prehensile tail of the 

 chamoelion enable it to creep with security on the agitated 

 branches ; the muscles of its eyes are not synchronous in 

 their movements, by which it commands an extensive field 

 of vision without moving its head, and the muscular, clavate, 

 prehensile tongue is moved w r ith velocity, like a sheath to 

 and fro, from the long body of the os hyoides. The power- 

 ful intercostals of the flying dragon expand its ribs with 

 their connecting skin, and move them like wings, to enable 

 it to pursue its insect prey through the air. The saurian 

 reptiles, possessing a more distinct cervical region than any 

 of the inferior vertebrata, and often carrying bulky prey to a 

 distance in their jaws, require a great development of the 

 muscles which suspend and move their heavy head and neck, 

 as the recti and obliqui muscles of the head, the splenii, sca- 

 leniy complexus and serratus posticus, the inter- and semi-spi- 

 nales colli, the transversalis, trapezius, and rhomboideus. 

 The fibres of ihepanniculus carnosus are intimately connected 

 with the large osseous, external plates of the loricated croco- 

 dilian reptiles, but the skin is more free in the lacertine spe- 

 cies. The external and internal obliqui abdominis and the 

 transversalis are distinct in the crocodiles, and also a rudi- 

 ment of the diaphragm. The posterior portion of the 

 diaphragm is likewise perceived in the dragons and geckos, 

 where it consists of muscular bands ascending from the bo- 

 dies of the vertebree to be attached to the ribs before 

 them. 



Many of the ordinary muscles of the trunk are wanting 

 in the chelonian reptiles, from the immobility of the skeleton 

 in that part of the body, especially in the land species. Se- 

 veral muscles of the face are deficient from the immoveable 

 horny covering of the jaws and lips, and from the close ap- 

 plication of the horny scales to the periosteum in that part. 

 The muscles on the dorsal part of the spine, and all the in- 

 tercostals, are likewise deficient. Those of the cervical, sa- 

 cral, and coccygeal regions, and those of the scapular and 

 pelvic arches, together with the muscles of the arms and 

 legs, are the most distinct and powerful in this order, and 

 correspond with the mobility of these parts, or the weight 

 they have to sustain. The temporal muscles are covered 

 over by the parietal bones in the turtles, but in the tortoises, 



PART II. M 



