Fig. 13.9 Composition by major groups among (a) crustacea, and (b) pelecypoda in
benthic samples collected from shallow to deep stations along the Gay Head to
Bermuda transect in the northwest Atlantic.
(^) (After Sanders et al. 1965.)
Third, or sometimes second, in abundance are the Pelecypoda or bivalve mollusks
(clams). In shallow waters, the dominant clams are eulamellibranchs, a group with
multiply divided gills, which are large in proportion to body size and employed in