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XXI. Observations on the Anatomy and Habits of Marine Testaceous Mollusca, 
illustrative of their mode of feeding. By Edward Osler, Esq. Communi- 
cated by L. W. Dillwyn, Esq. F.R.S. 
Read June 21, 1832. 
In studying- the Mollusca., we shall probably obtain more satisfactory results 
by tracing the organization connected with each important function through 
different classes of the animals, than by complete dissections of individual 
species. The data afforded by the first mode of investigation are more easily 
and effectually applied in future researches ; and as they necessarily connect 
the study of function with that of structure, they enable the zoologist to infer 
with tolerable certainty those habits, which the pelagic character of the ani- 
mal, or his inability to procure living specimens, prevent him from observing. 
Thus examining the mollusca in detail, we shall find no part of their orga- 
nization so interesting as that by which they take their food. Affording a 
general basis for scientific arrangement in the higher departments of zoology, 
it must be a still more certain key to the habits and general structure of those 
lower classes of animals in which the greater part of the organs are directly 
connected with this function. 
We ought not to be surprised that so little has hitherto been done to eluci- 
date the subject. The dissection is very difficult, from the small size and 
great softness of the parts ; and its results are often deceptive, for it is not 
always easy to determine whether any particular appearance be natural, or 
caused by the knife. The microscope affords very little assistance in distin- 
guishing the parts already dissected, and would be productive only of embar- 
rassment in the attempt to display them. 
Cuvier, in his work on the Mollusca, leaves this part of his subject nearly 
untouched. His allusions to it are for the most part but vague generaliza- 
tions ; and where he enters into detail, as in the trunk of Buccinum undatum, 
he falls continually into error. 
