710 



EEPTILIA. 



Fig. 351. 



on the one hand with the spinal nerves, and on the other giving off fila- 

 ments which form plexuses around the arterial trunks, and ramify exten- 

 sively to be distributed to the viscera. 



(2008.) The sense of 

 touch in all the members 

 of the class under con- 

 sideration must, from the 

 nature of their integu- 

 ment, be extremely im- 

 perfect : many of them, 

 in fact, as for example 

 the Serpent tribes, are 

 absolutely deprived of any 

 limbs which can be re- 

 garded as tactile organs ; 

 and even in those forms 

 which are provided with 

 efficient locomotive ex- 

 tremities, these are but 

 ill adapted to exercise 

 the functions of an appa- 

 ratus of touch. 



(2009.) The cuticular 

 investments of the body 

 are formed of dense 

 and unyielding materials, 

 consisting, in the higher 

 Reptiles, of broad horny 

 plates or of imbricated 

 scales. In the Amphibia, 

 indeed, the skin is smooth, 

 and the epidermis only 

 forms a delicate corneous 

 film ; yet even in these 

 the cuticle is thrown off 

 at certain seasons of the 

 year, as the old coat be- 

 comes too small for the 

 increasing size of the ani- 

 mal, a phenomenon which 

 in the Lizard and Serpent 



tribes is still more remarkably witnessed ; for these animals strip them- 

 selves of their old scales as the hand would be drawn out of a glove, and 

 cast away in one piece the entire epidermic integument, even to the film 

 which covers the transparent cornea of the eye. 



