SHARKS AND RAY-FISHES. 3 



impressed with the idea that the structure of the whole of them 

 is greatly inferior as compared with the more firm and intricate 

 structure of those which are termed bony fishes. We adopt 

 the energetic language of Mr. Owen on this subject, and remark: 

 "We should lose some most valuable fruits of anatomical study 

 were we to limit the application of its facts to the elucidation 

 of the unity of the vertebrate type of organization, or if we were 

 to rest satisfied with the detection of the analogies between the 

 embryos of higher and the adults of lower species in the scale 

 of being. We must go further and in a different direction to 

 gain a view of the beautiful physiological principle of the relation 

 of each adaptation to its appropriate function, and if we would 

 avoid the danger of attributing to inadequate hypothetical secon- 

 dary causes the manifestations of design, of supreme wisdom and 

 beneficence, which the various forms of the animal creation 

 offer to our contemplation. To revert then to the skeleton of 

 fishes with a view to the teleological application of the facts 

 or that which regards them as means directed to an end 

 determined by the study of this complex modification of the 

 animal framework. No doubt there is analogy between the 

 cartilaginous state of the endo-skcleton of Cuvier's chondrop- 

 terygians, and that of the same part in the embryos of the air- 

 breathing vertebrates; but why the gristly skeleton should be, 

 as it commonly has been pronounced to be, absolutely inferior 

 to the bony one is not so obvious. I know not why a flexible 

 vascular animal substance should be supposed to be raised in 

 the histological scale because it has become impregnated by 

 the abundant intussusception of earthy salts." 



"The rjredaceous Sharks are the most active and vigorous of 

 fishes; like the birds of prey they soar, as it were, in the ujiper 

 regions of their atmosphere, and without any aid from a modified 

 respiratory apparatus, devoid of an air-bladder, they habitually 

 maintain themselves 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 find well-marked modifications of the digestive and other 

 systems of the Shark by which the body is rendered as light, 

 and the space which eiicroaches on the muscular system as 

 small, as might be compatible with those actions. Besides, 

 lightness, toughness, and elasticity are the qualities of the 



