FEET or THE GECKO. 



31S 



nearly to the corresponding parts of the skeleton of the 

 higher orders of quadrupeds. The toes are usually provided 

 with membranes spread between them, to assist in swim- 

 ming. The form of the tail, which is generally compressed 

 vertically, like that of fishes, though perhaps not to an equal 

 degree, is another indication of their being formed for an 

 aquatic life: for where the tail has this shape, we always find 

 that the chief muscular power is bestowed upon it as an in- 

 strument of aquatic progression, producing, by its lateral 

 flexions, a horizontal movement of the body. Crocodiles 

 and alligators, for instance, which have this conformation, 

 are comparatively weak when on land, and as soon as they 

 have seized their prey, their efforts are always directed to 

 drag it with them into the water; knowing that when in 

 their own element they can readily master its struggles, and 

 dispose of it as they please. 



In the Gecko tribe, we find a particular mechanism pro- 

 vided for effecting the adhesion of the feet to the objects to 

 which they are applied. It is somewhat analogous to that 

 employed in the case of the house-fly, already mentioned. 

 Each foot has five toes; all, except the thumb, terminated 

 by a sharp curved claw. On the under surface of each toe 

 (represented in Fig. 211) there are as many as sixteen trans- 

 212 211 verse slits, leading to the same 



number of cavities, or sacsj 

 these open forwards, and their 

 external edge is serrated, ap- 

 pearing like the teeth of a small- 

 toothed comb. A section of 

 the foot, showing these cavi- 

 ties, is seen in Fig. 212. All 

 these parts, together with the 

 cavities are covered or lined 

 with cuticle. Below them are 

 large muscles wh ich draw do wn 

 the claw; and from the tendons 

 of these muscles arise two sets of smaller muscles, situated so 



