MOLLUSC A. 161 



classification: we arc, in candour, to place ourselves behind 

 its author, and, looking forward, say how far his efforts have 

 been useful or quickening." " The superiority of it lies in its 

 simplicity; in the regular subordination of all its parts; in 

 the admirable sagacity with which the families or genera are 

 limited;" in the conciseness of the specific characters, the 

 skill with which they were chosen, and the facility with which 

 species could be named. It labours under the censure of 

 having too small a regard to the animals, and to their position 

 in the groups, as regulated by the affinities of their organization. 



We now pass on to the labours of Baron Cuvier, who, 

 when scarcely nineteen years of age, went, in 1788, to reside 

 some time at Caen, in Normandy. There the marine mollusca 

 attracted his attention, and he commenced that series of 

 observations on their habits and investigations into their 

 anatomical structure which afterwards formed the sure and 

 enduring basis of his classification. Cuvier's object was not 

 merely "to give us a key to the name, but to make that key 

 open, at the same time, a knowledge of the structure and 

 relations of the creature." According to his system, the student, 

 when in search of the name and place of an object, was 

 obliged, at the same time, to acquire a knowledge of its 

 principal structural peculiarities. On these again, as Cuvier 

 beautifully explained, all its habits in relation to food, to 

 habit, and to locomotion, were made dependent. His division 

 of the animal kingdom into four primary groups or sub- 

 kingdoms has already been mentioned ; the essential character 

 of the mollusca, as one of these groups, has also been stated. 

 It is derived from the peculiar arrangement of the nervous 

 system, consisting of some ganglions scattered, as it were, 

 irregularly through the body, and from each of which nerves 

 radiate to its various organs. Their further division into 

 classes is founded on characters derived from the organs of 

 locomotion, or others not less influential. 



Since the time of Cuvier, the system which he propounded 

 has been elaborately worked out in detail by succeeding 

 naturalists, and has, from time to time, been slightly modified, 

 according to the advance of knowledge; but in its essential 

 characteristics it remains unchanged. Dr. Johnston, in speak- 

 ing of the effects of Cuvier's example and views, remarks: 

 "They raised the character of the conchologist, and gave a 

 more philosophical tone to his pursuit ; they originated a new 



