MUSCULAR SYSTEM. 147 



MUSCULAR SYSTEM. 



THE two sub-classes of Reptilia exhibit, even in the structure and 

 arrangement of their muscles, certain constant differences. 



The muscles of the Squamigerous Reptiles who rank nearest to 

 Birds and Mammalia, are of a redder color, more isolated and sep- 

 arated from each other into several bundles, and generally possess 

 greater energy of action, although those of the Frogs, which are 

 white, are endowed also with remarkable strength. In the Sirens, 

 and also in the Tailed Batrachia, the mode of arrangement of the 

 muscles is analogous to that of Fishes, their body, as in them, being 

 adapted for swimming. The distinctness and degree of separation 

 of the muscles increase as we approach the Sauria, in which the 

 muscles are most readily referred for comparison to those of the 

 human subject. In other respects such great diversities occur 

 throughout the class, that it were difficult to give a general de- 

 scription, without entering into more tedious detail than would be 

 compatible with the nature and extent of this work, and we must 

 therefore refer the student to the list of books and illustrations 

 given at the end of the class, for further information upon this 

 subject. 



The Tegumentary muscles are not always so developed in Rep- 

 tiles, as in Mammalia and Birds, and are completely wanting, for 

 example, upon the trunk of the Chelonia. Powerful and distinct 

 muscles of this kind are found, however, in the Serpents, upon the 

 ventral scutes, to the number of six pairs to each of the latter, which 

 by means of their action can be slid one within the other ; tegumenta- 

 ry muscles occur also in the Batrachia. 



The Ichthyic Reptilia, the Water-Newts, and the Tadpoles or 

 larvae of the Raniform Amphibia, which progress in the water by 

 inflecting trunk and tail, possess large laternal 'masses of muscle 

 similar to those of Fishes, which cover the whole back, and are 

 continued directly into the ventral muscles. The large lateral 

 muscle always arises from the occipital and temporal bone, and 

 from the arches and transverse processes of the vertebrae, and is 

 continued to the end of the caudal portion of the column. It is 

 usually intersected transversely by as many tendons as there are 

 vertebrae present. A superior and inferior layer of muscles may be 

 distinguished, which correspond to the m. sacro-lumbaris, and Ion- 

 gissimus dorsi. Besides the two oblique muscles of the abdomen, a 



