REPTILIA. 



287 



interims (Jig. 208, 23), and the triceps extensor 

 of the fore-arm. 



Fig. 208. 



Muscles of Salamander terrestris. 



On the fore-arm may be distinguished the 

 flexor carpi radialis (25), the flexor carpi 

 ulnaris (fig. 207, 26), the extensor carpi 

 ulnaris (27), the extensor carpi radialis (fig. 

 208, 28), a flexor com munis digitorum (29), 

 and an extensor communis digitorum (30). 



Muscles of the hinder Extremity. The 

 thick flexor of the thigh (fig. 207, 3 1), repre- 

 senting the iliacus internus, arises broadly 

 from the whole inner surface of the os ilei 

 passes over the os pubis, and is inserted into 

 the fernur below its middle. The long ex- 

 tensor and adductor of the thigh (32) arises 

 from the third and fourth caudal vertebrae, and 

 is inserted into the posterior aspect of the 

 femur about its middle. 



The long abductor of the leg (fig. 207, 

 33) arises from the external surface of the 

 os ilei, and is inserted into the tibia about its 

 lower third. The anterior abductor of the 

 thigh (figs. 207 and 208, 34) arises from the 

 anterior and internal surface of the os ilei, 

 and is inserted into a broad tendinous 

 expansion that covers the knee-joint. The 

 thin flexor of the leg (fig. 208, 36) arises from 

 the inferior lateral surface of the os ilei, and is 

 inserted into the outer part of the head of the 

 tibia. 



A long muscular slip (figs.207 and 208, 37) 

 arises from the transverse processes of the 

 third and fourth vertebras of the tail, and is 

 inserted into the back of the thigh bone. 



The chief muscle of the sole of the foot 

 (38) arises from the side of the sacrum, and is 

 inserted into the thick fascia of the sole. 

 The other muscles of the foot are an extensor 

 and abductor of the tarsus (39), which arises 

 from the upper end of the tibia, and is 

 inserted into the outer surface of the tarsal 

 bone. An extensor longus digitorum pedis 

 (40) arising from the fascia of the knee, and 

 the anterior surface of the ligaments of that 

 joint. This furnishes a tendon to each of 

 the five toes. The flexor longus digitorum 

 (41), arising from the upper extremity of the 

 tibia, and dividing into five tendons inserted 

 into the last joints of the toes. A short ex- 

 tensor arises from the entire anterior surface 

 of the bones of the tarsus : its tendons unite 

 with those of the long extensor. The short 

 flexor arises from the ankle joint, and giving 

 off fleshy fibres to the tendons of the long 

 flexor. There is likewise a special extensor 

 and abductor of the great toe, and a similar 

 one appropriated to the little toe. Both these 

 arise from the ligaments of the tarsus. Ex- 

 ternal and internal interossei muscles are 

 likewise present. 



The other muscles represented in the ad- 

 joining figures are the sphincter ani (42), and 

 a flexor of the tail (43), derived from the 

 transverse processes of the caudal vertebrae. 



The Teeth. The dental apparatus of the 

 Reptilia is so widely different in its construc- 

 tion in the different orders and even genera of 

 this class of animals, that no general description 

 of it is possible. We shall therefore quote 

 Professor Owen's * account of the various ar- 

 rangements adopted in the principal groups into 

 which they have been divided by naturalists. 



In the Deirodon scaber, the inferior spinous 

 processes of certain of the cervical vertebrae 

 are unusually prolonged, and penetrate the 



* Owen's Odontography, page 179, et seq. 



