538 HISTORY OF SYSTEMS. 



II. Section. C. monothalames. Shell unilocular, ex- 

 ternal, and containing the animal. 



Genus Ai'gonauta. 



III. Section. C. sepiares. No shell, either internal or 

 external. A solid, free, cretaceous, or horny body is con- 

 tained in the interior of most of these animals. 



The Genera are Octopus, Loligo, Loligopsis, and Sepia. 



Order V. HETEROPODES. 



There is no section in this order, nor families ; and the 

 genera are 



Carinaria. Pterotrachea. 



Phylliroe. 



You will observe, in this outline of Lamarck's system, the 

 conciseness and precision with which evei'y divisional limit is 

 charactered ; and the same precision with greater, yet not 

 with less distinct, fulness, he carries into the definition of his 

 well-selected genera, which are, again, illustrated with a co- 

 pious body of species characterised with rare excellence : and, 

 in this view alone, worthy to be studied as models for your 

 own guidance. Plence the main cause of the popular reception 

 of Lamarck's system, for these advantages adapted it to the 

 use of collectors, and of those who were engaged in naming 

 collections. You will often have to u.se it, and it may inter- 

 est you to know that blindness came with the publication 

 of the volumes that contain it, to deprive the author of that 

 sense most of all indispensable to a naturalist. He found his 

 assistant — the endeared substitute of a lost sense — as Lister 

 had done — in his daughter. She devoted her youth to the 

 promotion of the studies and fame of her parent, now stricken 

 with infirmity and age ; and so he finished a work on which 

 his future reputation must mainly rest. 



Before Lamarck had completed this system, Cuvier had 

 given to his the form and features which it was hereafter to 

 retain. This was in 1817 ; for, when republished by him 

 in 1830, it underwent no material alteration. There can 

 be no doubt of its superiority in its classical and ordinal sec- 

 tions, and even in the indicatioii of the principal families ; 

 but Cuvier neither attempted, nor seemed much to care, to 

 place families, genera, and species in that relationship and 

 degree to each other in which we please ourselves in dream- 

 ing that they were brought into existence, and stand in 



