Professor Owen's Teleology of the Skeleton of Fishes, 217 



modification of the animal framework. No doubt there is analogy 

 between the cartilaginous state of the endo-skeleton of Cuvier's Chon- 

 dropterygians, and that of the same part in the embryos of air-breath- 

 ing vertebrates ; but why this gristly skeleton should be, as it com- 

 monly has been pronounced to be, absolutely inferior to the bony one, 

 is not so obvious. The ordinary course of ago and decrepitude, or of 

 what may be called the decay of the living body, is associated with a 

 progressive accumulation of earthy and inorganic particles, gradually 

 impeding and stiffening the movements, and finally stopping the play 

 of the vital machine ; and I know not why a flexible vascular ani- 

 mal substance should be supposed to be raised in the histological 

 scale because it has become impregnated, and, as it were, petrified, by 

 the abundant intus-susception of earthy salts in its areolar tissue. It 

 is perfectly intelligible that this accelerated progress to the inorganic 

 state may be requisite for some special office of such calcified parts in 

 the individual economy; but not, therefore, that it is in an absolute 

 elevation of such parts in the series of animal tissues. 



It has been deemed no mean result of comparative anatomy to 

 have pointed out the analogy between the shark's skeleton and that 

 of the human embryo, in their histological conditions ; and, no doubt, 

 it is a very interesting one. But can no insight be gained into the 

 purpose of the all-wise Creator, in so arresting the ordinary course of 

 osteogeny in the highly organized fish ? Are we to entertain no 

 other view of it than as an unfinished, incomplete, stage of an hypo- 

 thetical Serial development of organic forms. 



The predaceous sharks are the most active and vigorous of fishes; 

 like the birds of prey, they soar, as it were, in the upper regions of 

 their atmosphere, and, without any aid from a modified respiratory 

 apparatus, devoid of an air-bladder, they habitually maintain them- 

 selves near the surface of the sea, by the actions of their large and 

 muscular fins. The gristly skeleton is in prospective harmony with 

 this mode and sphere of life, and we shall subsequently find as well 

 marked modifications of the digestive and other systems of the shark, 

 by which the body is rendered as light, and the space which en- 

 croaches on the muscular system as small, as might be compatible 

 with those actions. Besides, lightness, toughness, and elasticity, are 

 the qualities of the skeleton most essential to the shark ; to yield to 

 the contraction of the lateral inflectors, and aid in the recoil, are the 

 functions which the spine is mainly required to fulfil in the act of 

 locomotion, and to which its alternatinor elastic balls of fluid, and 

 semi-ossified bi-concave vertebrae, so admirably adapt it. To have 

 had their entire skeleton consolidated, and loaded with earthy matter, 

 would have been an encumbrance, altogether at variance with the of- 

 fices which the sharks are appointed to fulfil in the economy of the 

 great deep. 



Yet there are some who would shut out, by easily comprehended 

 but quite gratuitous systems of progressive transmutation and self- 



