ORGANIZATION OF ANIMALS. 199 



based on the identity, more or less complete, of the type ; 

 analogies, on a resemblance in the details. Thus the bat 

 (Fig. 108), a mammal, pterodactyle, a reptile, and the Dac- 

 tylopterus (106), or flying-fish, have no zoological affinity, 

 properly so called, excepting that they are vertebrate animals; 

 but they have remarkable analogies, being all organized for 

 flight, by having expansions of the integuments extended on 

 fingers prolonged for this purpose. Indeed, in contemptlating 

 and comparing with each other different zoological groups, 

 it would seem as if nature's tendency was to cause each 

 type to pass through a series of analogous modifications. 

 Thus amongst insects, spiders, and Crustacea we observe the 

 general plan of the organization modified in the same way, 

 according as the animal is intended to live on solid food, or as 

 a parasite by sucking the juices of another being. 



356. Organic Harmonies. In the midst of the innu- 

 merable variety in form and structure which the animal world 

 presents, may be observed a certain general harmony which 

 $eems to regulate all the parts of this vast creation ; and this 

 principle of co-ordination is all the more remarkable if we 

 restrict our observation to the entire of the structures com- 

 posing a single animal. Between every part there reigns the 

 strictest mutual dependence, so as to forbid all idea of chance 

 in its construction ; all are in the strictest accord. Some of 

 these harmonies are so obvious and striking that the natu- 

 ralist may, from the observation of a single organ a tooth 

 for example, deduce nearly the whole natural history of the 

 animal. From the subjoined figure (Fig. 154) may readily 

 be inferred that the animal had a skeleton, 

 a cerebro-spinal axis, nerves, &c. ; in short, 

 that it was a hot-blooded mammal, and that 

 it lived on flesh. In fact, from this single 

 organ may be deduced nearly the whole 

 structure of this carnivorous mammal, a 

 priori, or without having ever seen it. Pro- 

 ceeding on these principles of organic har- 

 monies, the true nature of the fossil organic 

 world was first discovered by Cuvier ; he it 

 was who first applied these laws to fossils, sso 



and by these means effected the restoration the Lion, 

 of an organic world long since extinct. 



[The law of organic harmonies must be applied with the 

 greatest caution. Cuvier seldom trusted to it ; it cannot be 



