MUSSEL FAUNA OF MAUMEE EIVEE. 



71 



Atax intermedins and Atax tumidus were also common on the 

 mussels in the reservoir. There were probably several other species 

 of Atax present; a small species with a red spot posteriorly was quite 

 common. Lampsilis alatus below the dam at Grand Rapids was 

 particularly heavily infected; in three examples 290 mites were 

 found, thus averaging about 97 per individual. 



Many of the Atax were full of eggs, and eggs and larvae in differ- 

 ent stages of development were common but not markedly abundant 

 on the inner side of the mantle and in the gills of the mussels. We 

 did not observe this year what was so conspicuous a feature in 1907 

 of the mussels found in the lakes about St. Paul, Minn., at the same 

 season of the year, viz, the young mites clustered thickly about the 

 papillae of the inhalent siphons. The mites were apparently not 

 breeding as heavily in the Maumee, and the young were not so far 

 advanced in development at the date examined. Atax probably pro- 

 duces considerable irritation in the mussel, but we have no evidence 

 that it affects shell characters. Where they bury their eggs in the 

 tissue of the mussel they leave small but conspicuous scars which are 

 apparently permanent. 



Although it has been suggested that the eggs of Atax may lead to 

 the formation of pearls, we have been unable so far to find con- 

 vincing evidence on this point. In our studies of mussels of the 

 Wabash Basin we obtained a great number of calcosphseric struc- 

 tures, many of them in situations that suggest a close relation to Atax 

 eggs. This subject is reserved for future investigation, as it does 

 not pertain to Maumee studies and would lead too far afield. 



Wherever we have examined mussels we have encountered the 

 parasite Gonchopthirus^ a protozoan bearing considerable superficial 

 resemblance to Parammcium. This organism is of such universal 

 occurrence that we have not taken trouble to specifically mention its 

 presence. There are several species {curtus, anodontw, etc.) para- 

 sitic on fresh-water mussels. 



GENERAL CONCLUSIONS. 



The Maumee River, as it exists to-day, is not on the whole a 

 stream where clamming operations could be carried on profitably, 

 as it would very quickly become exhausted if such operations were 

 undertaken on a large scale. The mussels were apparently once much 

 more numerous than at present. There are two conditions which 

 militate against the well-being of mussels in the upper part of the 

 river: The large amount of sewage, especially refuse from the gas 

 works, and the irregularity of flow of the river, which has been in- 

 creased by the removal of much of the original forest along the river 

 banks. The best mussel beds in the river are at Fort Wayne, Ind., 

 and below the dam at Defiance, Ohio. By far the greater number 



