Professor Owen's Teleology of the Skeleton of Fishes, 221 



The flattened form of the frontal and parietal bones in osseous 

 fishes has been associated with the small development of the brain 

 which they protect ; but observe how they would have impeded the 

 progress of the fish, had they been expanded into the dome-shaped 

 vault which arches over the skull of Birds and Mammals. There was 

 no need of that development in fishes ; but we must not overlook the 

 fact, th.at its very absence is a perfection in their structure, — an adap- 

 tation to their sphere and mode of locomotion. 



The loose connections of most of the bones of the face may like- 

 wise remind the homologist of their condition in the imperfectly de- 

 veloped skull of the embryos of higher animals ; but this condition is 

 especially subservient to the peculiar and extensive movements of the 

 jaws, and of the bones connected with the hyoid and branchial ap- 

 paratus. 



Not any of the limbs, properly so called, of fishes, are prehensile; the 

 mouth may be propelled and guided by them to the food, but the act of 

 prehension must be performed entirely by the jaws. Hence, in many 

 fishes, both upper and lower maxillary bones enjoy movements of pro- 

 traction and retraction, as well as of opening and shutting. The firm 

 connections of the upper jaw, and wedged fixity of the bone suspend- 

 ing the under jaw, which characterize the higher Reptiles and Mam- 

 mals, would be imperfections in the Fish; in which, therefore, such 

 characters are not only absent, but special development in the op- 

 posite direction not unfrequently goes so far as to produce the most 

 admirable mechanical adjustments of the maxillary apparatus, compen- 

 sating for the absence of hands and arms like those which have been 

 exemplified in the instance of the Epibulus insidiator (p. 108, fig. 

 37.) 



We must guard ourselves, however, from inferring absolute supe- 

 riority of structure from apparent complexity. The lower jaw of 

 fishes might, at first view, seem more complex than that of man, be- 

 cause it consists of a greater number of pieces, each rumus being 

 composed of two or three, and sometimes more separate bones. But, 

 by parity of reasoning, the dental system of that jaw might be re- 

 garded as more complex, because it supports often three times, or 

 ton times, perhaps fifty times, the number of teeth which are found 

 in the human jaw. We here perceive, however, only an illustration 

 of the law of vegetative repetition as the character of inferior organ- 

 isms ; and we may view, in the same light, the multiplication of 

 pieces of which the supporting pedicle of the jaw is composed in fishes. 

 But the great size, and the double glenoid or trochlear articulation 

 of that pedicle, are developments beyond, and in advance of, the con- 

 dition of the bones supporting the lower jaw in mammalia, and re- 

 late both to the increase of tho capacity of the mouth in fishes for 

 the lodgment of the great hyoid and branchial apparatus, and to the 

 support of the opercula or doors which open and close the branchial 

 chambers. The division of the long tympanic pedicle of osseous 



