SAURIAN REPTILES. -JOJJ 



and slender bones extend forw ards from the pubic 

 bones, on the under side of the body, apparently 

 for the purpose of supporting the abdominal vis- 

 cera.* The bones of the extremities are very per- 

 fectly formed, approaching in their shape and ar- 

 rangement very 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 swimming. The 

 form of the tail, which is generally compressed ver- 

 tically, 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 mus- 

 cular power is bestowed upon it as an instrument 

 of aquatic progression, producing, by its lateral 

 flexions, a horizontal movement of the body. Cro- 

 codiles 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 into the 

 water ; knowing that when they are in their own 

 element, they can readily master its struggles, and 

 destroy it by drowning. 



In the Gecko tribe, we find a particular me- 

 chanism provided 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 



* They appear to be analogous to the marsupial bones peculiar to 

 a family of Mammalia, comprising the Opossum, Kanguroo, Pha- 

 lanyer, Koala, Phascolome, &c. 



