MUSSEL FAUNA OF MAUMEE EIVEE. 13 



mussels were located was composed of mingled sand and pebbles. 

 The water over the mussel bed was shallow, averaging about 2 feet 

 in depth during the period of observation, and the current w^as mod- 

 erate, 3 or 3i miles per hour. The water varies considerably in 

 depth and turbidity at different times; even a small local shower 

 raises the surface perceptibly and makes the water very muddy, 

 after Avhich it slowly abates in volume and becomes clear. While 

 this mussel bed was under observation it was occasionally rendered 

 unworkable for a few days by local showers. On the other hand, the 

 water was sometimes found clear enough to see the bottom with a fair 

 amount of distinctness. 



The life conditions of the riffles and the swimming hole just above 

 it were studied in considerable detail. The river flora did not appear 

 to be particularly rich. The only conspicuous alga was a species of 

 Oscillatoria, which was very abundant on the surface in large floating 

 blue-black patches from which the filaments radiated in every direc- 

 tion. Of phanerogams, the only aquatic plants growing in the river 

 at this place were eelgrass or wild celery (VaUisneria spiralis) and 

 the dense-flowered Avater willow {Dianthera americana). 



The animal life was rich and rather varied. One of the most 

 abundant animals was a V ortic€lla-\\\iQ> protozoan, probably Epistylis^ 

 which thickly covered with a uniform hoary coating the blades of 

 VaUisneria and the branches and leaves of willow which dipped into 

 (he water. The same or a similar protozoan grew in great abundance 

 on the crawfishes of all sizes, especially thickly on the antennse, 

 which were rendered quite white and plumose. Examples of tKe 

 protozoan taken from the crawfishes showed the zooids thickly clus- 

 tered at the apex of a long nonretractile dichotomously branching 

 stem. On account of the nonretractility of the stem, this w^hite coat- 

 ing can not contract into a mass when irritated as can colonies of 

 Vorticella. A small colony of Vorticella was found clustered on an 

 Atax taken cvut of a mussel. A species of fresh-water sponge was 

 very common below the shell bed, frequently coating the inside of 

 dead valves with an expanded thick feltlike covering. The brown 

 hydra {Hydra ftcsca) was quite abundant, and numerous examples 

 were seen attached to the back of shells of Ancyhcs. Leeclies did 

 not seem to be abundant; the only one noted was a fish leech attached 

 to a sunfish caught in the river. 



In addition to the mussels, discussion of which will be reserved 

 till the end of the description of the locality, various univalves such 

 as Pleurocera, Physa, and Ancylns were common. 



The crawfishes were so abundant at this place as to deserve special 

 mention. So far as examined the species was Camharus virilis 

 9275°— 13 7 



