540 HISTORY OF SYSTEMS. 



plexity, partly from its anatomical character, and partly be- 

 cause of its harsh and new nomenclature, a great and just 

 bar to the easy reception of any system. Blainville's appears 

 to have been invented in 1816, but by a curious accident it 

 was not published until 1825, for his " Manuel de Malaco- 

 logie et de Conchy liologie " was written for a British Ency- 

 clopaedia, and, being mislaid by Dr. Leach, was lost for some 

 years. In the meantime, however, M. de Blainville gave an 

 outline of a method in his " Principes d'Anatomie com- 

 paree," published in 1822 ;* and there is something so 

 curious and novel in his general distribution of the animal 

 kingdom, when taken in connection with certain modern 

 theories as to a natural system, that I shall copy out for your 

 perusal (page 541) such portion of it as has an immediate refer- 

 ence to our subject. You may observe that, as if in ridicule 

 of his predecessor's self-elevating hypothesis, the Mollusca 

 are made to proceed out from the vertebrated fishes, with a 

 widely intervening chasm of separation between them ; 

 Nature being made both to leap and to descend from per- 

 fection to imperfection, which she can do, believe me, just 

 as easily as she can ascend on the contrary direction. You 

 may also remark that a new principle is introduced into the 

 arrangement of the Mollusca derived from the condition of 

 their reproductive organs, a principle of questionable utility 

 even were its physiological correctness admitted, because it 

 is recondite and not to be easily seized upon ; and not being 

 sufficiently impressive in the animal's economy, it is found 

 to put too far asunder genera evidently more nighly affined. 

 I quite agree with Mr. Swainson in his objection to the use 

 of internal anatomy in classification, f External structure is 

 just as important for this purpose ; and we know that it is 

 in fact an index to interior organisation, which it is surely 

 unnecessary to specify in the outline or definitions of a 

 method. 



I take the subjoined outline of De Blainville's system from 

 his Manuel, J in which the characters of every division, from 

 the type to the genus, are given with elaborate care. 



Type Malacozoa. 



Class I. CEPHALOPHORA = Cephalopods. 

 Order I. CRYPTODIBRANCHIATA= Sepia, Lin. 



* De 1'Organization des Animaux ; ou, Principes d'Anatomie comparee, 

 par M. H. M. Ducrotay de Blainville. Paris, 1822, 8vo. The first volume 

 only has been published. 



t Prel. Discourse on Nat. History, p. 84. 



One vol. 8vo. with an atlas. Paris, 1825. 



