150 College of Forestry 
when their shells have been crushed. It was also seen to en- 
gulf and retain the feeces of other snails.” These snails were 
seen to rasp off pieces of Lemna, both living and dead, and 
green apples placed in the aquarium were greedily eaten. Col- 
ton (1908, pp. 420-425) states that the food of Lymnea con- 
sists normally of diatoms, desmids, unicellular and filament- 
ous alge. This author fed Pseudosuccinea columella on 
Myriophyllum and Llodea, these water plants being eaten by 
some and refused by others. The writer (1911, pp. 42-44, 147, 
170, 190, 311, 414) has recorded many observations relating 
to food of the Lymneas, which is here summarized. Lymnea 
stagnalis appressa was observed to feed upon dead animals 
and rotten vegetables and it is said to attack small fish 
(stickleback). Pseudosuccinea columella has been seen feed- 
ing on decaying water plants and pond scum (Sptrogyra). 
The large Bulimnea megasoma feeds on pond lily leaves and 
has been known to devour the animals of land snails and fresh 
water mussels with great greediness. In Lake Cobalt, Can- 
ada, this species lives in water strongly impregnated with 
arsenic. Galba palustris is omnivorous, eating vegetation, 
rotten fruit or decaying vegetation, dead animals and even 
attacking living animals (a leech). Galba emarginata is said 
to feed on the confervoid algze on the rocks in Maine. 
In quiet bays and ponds a bottom soil is sometimes formed 
chiefly by the excrement of the bottom fauna and plant re- 
mains. Such a bottom soil is known as gytje among the 
Danish biologists. This condition has not been observed in 
Oneida Lake. 
Examination of Stomach Contents of Lymnza. 
In order that definite information might be secured con- 
cerning the food of the large Lymnas, the crop of a number 
of examples of Lymnea stagnalis lilliane were examined. It 
will be observed that bryozoan statoblasts form 3.75 per cent., 
Planorbis 10 per cent., and alge and plant fragments 86.25 
per cent. Only one individual of the five containing food 
had eaten animal matter, in this case the mollusk, Planorbis 
