156 



MUSCULAR SYSTEM. 



state, the muscular system is the most remote from that of 

 fishes in its general characters and in the disposition of its 

 parts, which arises from their greater extent of respiration, 

 their inhabiting a rarer medium, the great development of 

 their extremities, and the large portion of the trunk which 

 they lose by their metamorphosis. Their muscles are more 

 vascular, dense, red-coloured and strong, more distinct and 

 defined in their course and in their insertions, more ventri- 

 cose, seldom exhibiting parallel strata, and generally inserted 

 into distinct and often lengthened tendons. From the leap- 

 ing and swimming habits of many of these species, we per- 

 ceive their short trunk terminated by lengthened and strong 

 legs and provided generally with less perfectly developed 

 arms, and the greater development of the extensors than of 

 the flexors of the legs, gives an anthropoid character to these 



extremities. In the back 

 view of the muscular system 

 of the common frog, rana 

 esculenta (Fig. 73,) the small 

 size of levatores scapulae, (1. 

 2,) corresponds with the 

 soft and feeble condition of 

 the dorsal portion of these 

 bones into which they are 

 inserted. The depressor of 

 the lower jaw (5,) the sca- 

 pular (6,) and the sub-sca- 

 pular muscles (8,) occupy 

 the anterior part of the back 

 immediately behind the head, 

 having before them the broad 

 temporal muscles, and be- 

 hind them the quadratus 

 lumborum, (19, 24,) the sa- 

 cro lumbalis, (23,) and the 

 dorsal portion of the obliquus 

 externus (22.) The ilio-coccy- 

 geus, (25, 26,) is of great 

 length, like the coccygeal 

 bone, and the ilium to which 

 it is attached, and the trans- 



FIG. 73. 



