MYOLOGY OF REPTILES. 219 



strips from the second and third cervical diapophyses, inserted 

 into the under part of the scapula, indicate the commencement of 

 the serratus magnus anticus, fig. 141, 21. The mass of muscle, 

 figs. 140, 141, 23, which protracts or 'flexes' the fore-arm, aris- 

 ing from the fore and inner part of the glenoid cavity and from 

 the fore part of the humerus, represents the biceps and brachialis 

 internus. The retractor or extensor mass, ib. 24, answers to 

 the divisions of the triceps. On the antibrachium the flexor of 

 the wrist is divided into a 'radial,' fig. 141, 25, and 'ulnar,' 

 fig. 140, 26, portion; as is likewise the extensor, of which, 27, 

 fig. 141, represents the extensor carpi ulnaris, and 28 the extensor 

 carpi radialis : 29 is the flexor digitorum communis, and 30 the 

 extensor digitorum communis. 



The pectoralis, fig. 141, 16, is represented in the pelvic limb 

 by the muscle, ib. 36, which arises from the ischiopubic sym- 

 physis, and is inserted into the front and inner part of the 

 head of the tibia. This mass in higher reptiles becomes dif- 

 ferentiated into the pectineus, the adductors, and the gracilis ; 

 it depresses and adducts the pelvic limb. Its chief antagonist 

 is marked 36 in fig. 140. It rises from the ilium, and is inserted 

 into the lower and outer part of the femur, and also into the 

 outer part of the head of the tibia ; it corresponds by its origin 

 with 22 in the fore limb, and becomes developed into gluteus 

 externus and ' tensor fascice femor is'' in Mammals. The fasciculi 

 which correspond with 11, in the fore-limb are 37 and 32, fig. 140; 

 they arise from fascia connected with the transverse processes of 

 the third and fourth caudal vertebrae, and are inserted into the 

 middle and back part of the femur. The muscle, 31, which arises 

 from the fore part of the ilium, and is inserted into the upper 

 third of the femur, repeats the anterior fibres of 22 in the scapular 

 limb. The chief difference is that the protractors, 31, and retrac- 

 tors, 32 and 37, of the thigh are more distinct from the abductor 

 and levator, 36 ; and that this has a more advantageous insertion 

 for its office by being extended to the second segment of the 

 limb. The retractors, 32, 37, act like the latissimus dorsi 11 : their 

 origin is in connection with the vertebral or axial system : they 

 become developed in the pelvic limb of higher animals into parts 

 of the ' glutei ' and ' pyriformis.' 



The protractors or flexors of the thigh, 34, 35, which answer to 

 those of the arm, 23, arise from the fore and under part of the 

 ilium, and are inserted into the fore and upper end of the tibia. 

 The muscle, fig. 141, 35, which passes to the inner side of the head 

 of the tibia, answers best to the sartorius ; the larger mass on its 



