CULTURE OF FRESH-WATER MUSSELS. 



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the quieter waters of rivers. This was the Lake Pepin mucket, Lampsilis luteola 

 (Lamarck). In this mussel a surprising amount of growth took place during one 

 season. The other species fared less well, in some cases apparently surviving only a 

 short period. Since satisfactory positive results were attained with L. luteola, the 

 experiments with this species furnished a basis for comparison of the methods in 

 reference to their influence on growth. As the results with this species may have 

 been largely due to inherent qualities, a short account of its natural history and 

 development seems desirable. 



The Lake Pepin or fat mucket, as it is generally called, has a shell of excellent 

 quality and possesses a good reputation as a pearl producer. It is probably the most 

 widely distributed of the fresh-water mussels used commercially. Simpson (1900) 

 gives its distribution as follows: Entire Mississippi drainage southwest to the Brazos 

 River, Tex.; St. Lawrence drainage; entire Dominion of Canada east of the Rocky 

 Mountains. The author has found it under the most varied conditions — from those 

 of the marshy slough of a small creek to the deep waters and 'wave-beaten beaches of 

 the Great Lakes. These observations would indicate that the form is adaptable to 

 widely varying environment and would, perhaps, explain its thriving condition in this 

 experiment where other species fared less well. 



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Figs. 67 and 68. — A young mussel on: to three days after leaving the fish, in outward form like the original 

 glochidium but internally (tAt is. inside the shell) showing organs developed. Drawn with a camera 

 lucida. X 140. 67.— Ventral view with valves apart, from specimens stained and cleared. 68. — Side 

 view; a narrow growth of the new definitive shell may be seen bordering the glochidial shell. 



This species belongs to the bradytictic group called winter breeders. The glochidia 

 are produced in the late summer or fall and are carried through the winter in the dis- 

 tended marsupial gills (see fig. 62) of the female. The glochidia (fig. 64) are favorable 

 for infection, because their comparatively large size makes it easy to follow the progress 

 of infection (fig. 65) and subsequent shedding. Unfortunately, the number of glochidia 

 produced is relatively small. 



The gravid mussels for this experiment were obtained in Lake Pepin, Minn., about 

 May 15, 1914, and shipped to Fairport, Iowa, by express. On May 21 ripe glochidia 

 were taken from three of the live mussels for the experiment. Some dozen different 

 species of fish were infected and of these, six proved susceptible and carried the young 

 mussels through their metamorphosis. Before the young mussels began to be shed 

 eight infected largemouth black bass were placed in basket No. 2 of the floating crate. 

 Some very rough weather followed, tossing the crate about in such a way as to make 



