MUSSEL FAUNA OF MAUMEE KIVER. 



47 



contained great numbers of Atax) the largest number of individual 

 parasites. 



Most of the shells obtained were more or less stained red interiorly. 

 This stain, caused by a parasite, the distomid of Osborn, varied 

 greatly in extent, beginning in the umbonal cavity and extending 

 from that region in two diverging lines, one anteriorly and the other 

 posteriorly, ventrad. The V-shaped area thus formed gradually fills 

 in with red until the whole surface is involved. This process has 

 been quite fully described by H. L. Osborn'^ and by H. M. Kelly.^ 

 The minute distomids, showing pink against the mantle, were present 

 in numbers varying from a few to several hundred. 



Occasionally mussels of this species were found in which the dis- 

 tomids mentioned above had not yet escaped from the sporocysts. 

 The shells of such mussels frequently had the nacre raised in sharp 

 pearlj^ projections, and in some cases the sporocysts seemed to have 

 been overgrown with the nacre of the shell. 



In addition to the distomid of Osborn, A. grandis also usually has 

 a number of As fidog aster conchicola in the pericardial cavity, several 

 individuals of Cotylaspis insignis in the axils of the inner gills, and 

 one or more species of Atax among the gills; even leeches are fre- 

 quently found within the shells. The leeches are no doubt parasitic, 

 as is evidenced by the fact that where a pile of freshly cleaned shells 

 killed by muskrats were found under water on another occasion (at 

 Lake Maxinkuckee) the leeches almost covered the insides of the 

 valves. 



On account of the thinness of its shell, Anodonta grandis^ and 

 indeed all the species of this genus, are of no value commercially. 



16. Anodonta imhecillis (Say). This species has not heretofore 

 been reported from the Maumee Basin. It was only infrequently 

 found; one specimen was obtained on the shore of the St. Marys 

 Eiver, at Fort Wayne. After this none were seen until at the very 

 end of the investigation, in the canal at Maumee, Ohio, below the 

 dam; at this place 38 examples were taken. Their abundance here 

 indicates that they were probably abundant also throughout the 

 length of the canal, but do not " bite " at the dredge hooks. As none 

 were found in the bottom of the feeder canal, it is probable that they 

 do not occur there. This is a very pretty species, but it is of no com- 

 mercial value. 



17. Strophitus edentulus (Say). Squaw-foot. This species is not 

 common in the Maumee Basin. Examples were occasionally found 

 in the St. Marys River at Fort Wayne, in the feeder canal, and in the 

 St. Joseph and upper Maumee Rivers. One was obtained at Grand 



« Zoological Bulletin, vol. i, no. 6, 1898. 



''Bulletin Illinois State Laboratory Natural History, vol. v, p. 406, 1899. 



22367°— 12- 



