48 



ESSAY ON CLASSIFICATION, 



Part I. 



the Plovers, the Gulls, the Ducks, the Pelicans; among Reptiles, the Crocodiles, the 

 difterent families of Chelonians, of Lizards, of Snakes, the Frogs proper, the Toads, 

 etc. ; among Fishes, the Sharks and Skates, the Herrings, the Codfishes, the Cyprin- 

 nodonts, the Chtetodonts, the Lophobranchii, the Ostracionts, etc. ; among Insects, the 

 Sphingoidaj or the Tineina, the Longicorns or the Coccinellina, the Bomboidce or the 

 Brachonidae; among Crustacea, the Cancroidea or the Pinnotheroida^, the Limuloidce 

 or the Cypridoidse, and the Rotifera;^ among Worms, the Dorsibrauchiata or the 

 Naioidoe ; among Mollusks, the Stromboidse or the Buccinoidoe, the Helicinoida3 or the 

 Limna^oido?, the Chamacea or the Cycladoidie ; among Radiata, the Asterioidaj and 

 the Ophiuroidfe, the Hydroids and the Discophora^, the Astra^oidfe and the Actinioida?. 



Having thus recalled some facts which go to show what are the limits within 

 which size and structure are more directly connected,^ it is natural to infer, that 

 since size is such an important character of species, and extends distinctly its cycle 

 of relationship to the families or even further, it can as little be supposed to be 

 determined by physical agents as the structure itself with which it is so closely 

 connected, both bearing similar relations to these agents. 



Life is regulated by a quantitative element in the structure of all organized 

 beings, which is as fixed and as precisely determined as every other feature depend- 

 ing more upon the quality of the organs or their parts. This shows the more 

 distinctly the presence of a specific, immaterial princijjle in each kind of animals 

 and plants, as all begin their existence in the condition of ovules of a microscopic 

 size, exhibiting in all a wonderful similarity of structure. And yet these primitive 

 ovules, so identical at first in their physical constitution, never produce any thing 

 different from the parents; all reach respectively, through a succession of unvarying 

 changes, the same final result, the reproduction of a new being identical with the 

 parents. How does it then happen, that, if ph3^sical agents have such a powerful 

 influence in shaping the character of organized beings, we see no trace of it in the 

 innumerable instances in which these ovules are discharged in the elements in which 

 they undergo their further development, at a period when the germ they contain, 



^ See Dana's Crustacea, p. 1-109 and 1411. 



^ These remarks aliout the average size of ani- 

 mals in relation to tlieir structure, cannot fail to 

 meet with some abjections, as it is well known, 

 that under certain circumstances, man may modify 

 the normal size of a variety of plants and of 

 domesticated animals, and that even in their natural 

 state occasional instances of extraordinaiy sizes 

 occur. But this neither modifies the character- 

 istic average, nor is it a case which lias the 



least bearing upon the question of origin or even 

 the maintenance of any species, but only upon 

 individuals, respecting wliich more will be found in 

 Sect. 16. Moreover, it should not be overlooked 

 that there are limits to these variations, and that 

 though animals and plants may be jjlaced under 

 influences conducive to a more or less voluminous 

 growth, yet it is chiefly under the agency of man, 

 that such changes reach their extremes. (See also 

 Sect. 15.) 



