The Relation of Mollusks to Fish in Oneida Lake 123 
invariably found on the rocks and not on the sand. Galba 
and Planorbis live on both sand and rocks. Habitat XX XIII 
is one of the poorest in number of individuals, although sup- 
porting six species (Figure 33). The small number of gas- 
tropods is noteworthy. No. XI is the poorest habitat in both 
species (2) and individuals (7). This is a wave-swept point, 
too violent for gastropod life, but apparently favorable for 
bivalve life. Stations XX VI and XXX are especially favor- 
able for gastropods, notably Galba catascoprum, which is 
abundant. 
an meet Ao ea meen, 
\ 
\ 
Fig. 33. Diagram illustrating quantity of mollusks in one square foot 
at station XXXIII, a boulder habitat, water 16 inches deep, 
14 specimens present. 
l. Lampsilis radiata (2). 5. Planorbis campanulatus (1). 
2. Margaritana margaritifera (1). 6. Physa ancillaria warreniana 
3. Elliptio complanatus (5). (2). 
4. Galba catascopium (3). 
