60 MUSSEL FAUNA OF MAUMEE EIVER. 



water-bloom aliifr. These may serve also as food. The stomach con- 

 tents of such mussels, when placed in vials of preservative, differen- 

 tiate into a lower stratum of black mud and an upper flocculent 

 stratum of fairly pure algse. 



The mussel may be regarded as a sort of living filter, feeding upon 

 the filtrate it separates from the water. It would be worth investi- 

 gating to ascertain wdiether they arrest and destroy pathogenic 

 bacteria and thus become elRcient purifiers of water. They are valu- 

 able aids in plankton investigations, capturing many minute organ- 

 isms which escape methods ot^ collection ordinarily in use. Though 

 at the outset it hardly looks as if they could cope with the problem, 

 their capacity for ingesting water-bloom algse {Glathrocystis^ 

 Lynghya^ etc.) suggests that it might be worth while to investigate 

 their efficiency as reducers of plankton scum. 



The water bloom, as is well known, frequently becomes a nuisance. 

 It collects in noisome masses of scum along shores of otherwise at- 

 tractive lakes and reservoirs. Its taste and odor renders the water 

 of reservoirs undrinkable, and for a remedy of this condition the 

 copper sulphate treatment has been devised. Its presence in large 

 quantities along the shores of our most beautiful lakes renders them 

 unattractive during the late summer season, and in many places 

 brings the bathing season to an early close. Aside from the filthy 

 appearance of the water, many persons claim to be actually poisoned 

 by the water bloom, and there are instances on record of live stock 

 being fatally poisoned by drinking water covered with plankton 

 scum. In addition to this, the gTeat amount of decaying mate- 

 rial in the water is said to take up oxygen, making the lower 

 strata uninhabitable for fish. It is possible that by planting large 

 numbers of mussels, supplemented by planting egg masses of Ghiro- 

 nomus, which appear to hatch easily and the larvae of which eat the 

 coarser algse, that the plankton-scum nuisance can be greatly abated. 



The stomach contents of mussels taken from the main current of 

 the St. Marys, St. Joseph, and Maumee Rivers were rather note- 

 worthy for their paucity of organic material. Through the large 

 mass of muddy matrix filling the stomach were usually scattered a 

 few Scenedesmus^ various diatoms, and an occasional Pediasti-um or 

 Cosmarium. At the riffles small brown cystlike objects, which may 

 have been a species of TracheTcmonas^ were quite common ; with the 

 exception of this the mussel contained very little. Among the organ- 

 isms noted were Seenedes7nus caudatus, Gmlastrum microsporum, 

 Pleurosiffma, several forms of Navicnla, Phacus longicaudus, Pe- 

 diasti^m haryamim^ Gomplionema^ a sponge spicule, and an active 

 EuglenaASk^ organism. The stomach contents of mussels taken else- 

 where along the river and in its tributaries, as in the Auglaize at 

 Defiance and the Maumee at Grand Rapids, Avere not essentially dif- 



