86 
distinction of the vertebrz into cervical, dorsal, or 
lumbar, but, as in fishes, merely into dorsal and 
caudal‘. In the perfect frog the caudal are wanting; 
there is only a strait elongation of the os coccygis. 
In salamanders the caudal vertebre are 27. In 
these, as in fish, joints with opposing cavities, filled 
with fluid, facilitate the lateral motions of the spine. 
One of these cavities in a shark was found to con- 
tain three pints of fluid. 
Of 41 vertebre in a carp 16 are caudal: in the 
turbot, gadus lota, the vertebrz are 57, caudal 33, 
The number of vertebrz in proteus anguinus is 
59, caudal 27. In eels the total is 115, in the shark 
above 200. 
“ 'The fins, which in fishes supply the place of ex- 
ternal extremities, may be considered as hands for 
swimming, provided with numerous and delicate 
fingers, often having numerous articulations, as in 
rays *.” 
The general use of bones is their operation as a 
fulcrum and stay to the muscles. In this view the 
shells of the crustacea will be found analogous to 
the skeletons of the vertebrata. 
In a review of the organs of motion, Carus ob- 
serves, “ In the lower species of animals, worms and 
slugs, (mollusca,) we find the body frequently with- 
out any solid parts serving as points of support dur- 
ing motion: in others, on the contrary, as testacea, 
insects, and crustacea, in addition to muscles, the 
Pps u37, 038: k Pag. 125. 
