58 MOLLUSCA. 
and Montaga stand acquitted. The former has given us 
several good dissections, and the latter minute descriptions 
of the testaceous animals. 
Whilst, in the preceding remarks, we have objected to all 
arrangements taken exclusively from the characters of the 
shell, we also disapprove of those systems founded exclu- 
sively on the characters of the animal. By the former class 
of methodists, the simplicity of nature is sacrificed to their 
peculiar views, and, by the latter, practical utility is disre- 
garded. Devoting their whole attention to the animal, the 
later naturalists have overlooked the house in which it 
resides ; the roof which shelters it from the blast; and the 
walls which guard it from its foes. The former observ- 
ers possessed very limited views of nature, and erected 
systems obviously artificial. To the systems of the latter, 
the same objections will apply. Thus, for example, among 
the univalves of Adanson, the families are formed from the 
position of the eyes chiefly. That the black points which 
we witness at the tips or at the base of the tentacula are 
actually eyes, we readily admit ; but what influence have 
these eyes on the habits of the animal? or rather, does a 
change of position of these organs occasion a corresponding 
change in the habits of the animal? Unless thisis answered in 
the affirmative, we must consider such characters as equally 
artificial with any employed by Linnzeus or his followers, 
since they have no relation to any of the primary functions 
of life. 
The employment of characters taken exclusively from the 
animal is attended with so many practical difficulties, that 
it never can be introduced into general practice. If we find 
a shell thrown ashore, the animal may be dead, or it may re- 
fuse for a time to display its organs, and prevent us from 
