SCATOLOGICAL STUDIES OF THE BIVALVIA (MOLLUTSCA)
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macoma etc.), Psammobiidae (Gari), Ungulinidae (Joannisiella), Mesodesmatidae (Caecella), Cardiidae (Trigonocardia) and Xylophaginidae
(Xylophaga). The shape is oval and rounded in section. Both ends are
normally rounded or occasionally flattened. The surface is unsculptured, homogeneous and very resistant. The ratio of length to breadth
of pellets usually ranges within the limits of 1.0 to 2.0.
Pellet-type la. Discoid
This type of pellet is probably produced by Macoma (Tellinidae),
Barnen (Pholadidae) and Abrina (Semelidae). The shape is discoidal
1
l a
3
5
6
7
7a
7 b
80
9
9a
1 0
II
Fig. 2. Schematic representation of various typw of bivalve faecal pelletn. For numbering see Table T.