lOO BULLETIN OF THE BUREAU OF FISHERIES. 



supposed that the conditions in these waters are not favorable to the production of 

 good shells. Certain species are mentioned, however, which, in other regions at least, 

 possess shells of commercial quaUty. Principal among these are the following : 



Maple-leaf, Quadrula lachrymosa (Lea). 

 Pimple-back, Quadrula pustuhsa (Lea). 

 Pig-toe, Quadrula undaia (Barnes). 



Long solid, Quadrula subrotunda (Lea). 



Hickory-nut, Obovaria ellipsis (Lea). 



Black sand-shell, Lampsilis recta sageri (Conrad). 



Clark, collecting on the shores of Lake Erie at Put in Bay, found dead shells all 

 dwarfed in form but representing 14 species, of which the more common were as follows: 



Three-ridge, Quadrula undulata. 

 Spike, Vnio gibbosiis. 

 Round hickor>'-nut , Obovaria circulus. 

 Paper-shell, Lampsilis gracilis. 



Pink heel-splitter, Lampsilis alata. 

 Black sand-shell, Lampsilis recta. 

 Fat mucket, Lampsilis luteola. 

 Pocketbook, Lampsilis ventricQsa. 



PONDS, SLOUGHS, MARSHES, AND SWAMPS. 



These types of environment are grouped together, since their mussel fauna is gener- 

 ally similar. The mussels are thin-shelled as a rule, since light weight is favorable for life 

 in mud or soft bottoms and mass is not essential in the absence of current. Some possess 

 narrow bodies and keel-like shells that fit them for locomotion through soft soil, and a 

 few of the narrow-bodied species, where other conditions are suitable, have relatively 

 heavy shells. Such are the pink heel-splitter, Lampsilis alata, and the white heel- 

 splitter, Symphynota complanata. 



The heavier mussels characteristic of rivers are sometimes found in sloughs, but in 

 these the characters of flowing and still water are in a measure combined, since strong 

 currents may prevail at seasons of high water. Sloughs, as parts of river systems and 

 subject to being stocked from them, have mussel fauna to a certain extent related to 

 that of the river ; that is, the still- water species of the river are to be found in the sloughs. 

 Marshes and swamps may have mussels at places where they contain pond or streamlike 

 openings. In general the marsh and swamp environment is not favorable to mussels. 



In ponds that are more or less isolated the thin-shelled mussels of the toothless 

 type, as Anodonta grandis (floater) and Anodontoides jerussacianus, are characteristic. 

 Lampsilis parva, one of the tiniest of fresh-water mussels, scarcely exceeding an inch 

 in length, is sometimes found in such environments. A characteristic pond-dwelling 

 species is the mussel Unio Mralasmus, which will survive in ponds that become dry in 

 summer. Examples of this species of mussel have been found alive buried in the bottom 

 three months after the water had disappeared on the surface (Isely, 1914, p. 18). 



ARTIFICIAL PONDS AND CANALS. 



Artificial ponds may present a favorable environment for many species of fresh- 

 water mussels if the water supply is suitable, and some species are likely to become 

 accidentally introduced with fish that are brought into the pond. The ponds of the 

 Fisheries Biological Station at Fairport, Iowa, are supplied with water pumped from 

 the Mississippi River. The first species of mussel to appear in the ponds was the large 

 thin-shelled slop-bucket, Anodonta corpulenta, some examples of which had attained a 

 length of 3 to 3^^ inches when they were first discovered at the expiration of the second 

 season of the pond, 17 months (May, 1910, to October, 1911) after the date of introduc- 



