473 
which the aquatic life crowds at this season of the year. js The bottom 
of the river is composed of sticky blue clay. The whole area iS 
much trodden by the feet of cattle. 
The principal plant life of the river is as follows: 
Polygonum pennsylvanicum Pennsylvania Persicaria. 
Polygonum hydropiperoides. | Mild Water-Pepper. 
Iris versicolor. Large Blue Flag. 
The Polygonum forms large masses in the shallower portions’ of 
the river. 
MOLLUSKS. 
The molluscan fauna of the stream is quite varied, the mollusks 
being able to adapt themselves to the rigorous'summer conditions, 
at which time they retreat to the small pools which are left in the 
deeper parts of the stream. 
The appended list of species is large, considering ne character 
of the habitat. 
Lampsilis parva. Common. 
Anodonta grandis. Common. 
Anodontoides ferussacianus. Occasional. 
Spherium stamineum. Abundant. 
Musculium transversum. Abundant. 
Physa gyrina. Abundant. 
Ancylus rivularis. Common. 
Planorbis trivoluis. Abundant. 
Planorbis parvus. Common. 
The pelecypods thrive in the soft blue clay, the unionids in the 
deeper parts, the sphzeriids along the shore in shallow water. Ancylus 
rivularis and Planorbis parvus live on the stems of rushes. 
INSECTS. 
The insect life of the river is apparently the same as that in the 
larger ponds and pools of the intermediate ridge. The following 
were observed: 
Limnotrechus marginatus. Water-strider. 
Corixa interrupta. Water-boatman. 
Zattha fluminea. Water-bug. 
Dineutes assvmilis. Water-beetle. 
Notonecta undulata. Back-swimmer. 
