14 MUSSELS OF BIG BUFFALO FORK OF WHITE RIVER. 



DISTRIBUTION Or MUSSEL SPECIES. 



Red niggerhead^ Quadrula tuberculata {Rafnesque). — Rather com- 

 mon throughout the whole extent of the river traversed. The 

 species is represented by 78 examples of various sizes, none very large 

 and none very small. The shells do not exhibit much variation; 

 they belong to a small, somewhat inflated type, much like those 

 found in the streams of Kentucky and Tennessee. The specimens 

 taken at station 6 were rather inflated comi")ared with the others, 

 and those obtained at station 26 were relatively small and thin. 

 None were sufficiently inflated, however, to be regarded as Q. grani- 

 fera, which diifers from this species chiefly in degree of inflation, 

 and none was so flat as the fine specimens of Q. tuberculata found in 

 the Maumee^ Tippecanoe, and Wabash Rivers, where the species 

 appears to reach its finest development. All lacked the fine wavy 

 sculpture of the umbones w^hich is characteristic of the young of Q. 

 tuberculata in its most perfect conditio^i. The name " red nigger- 

 head " was applied to this shell at the pearler's camp below Gilbert. 

 On account of its colored and lusterless nacre this shell has little com- 

 mercial value. 



It was found at the following stations: 3, scarce; 5, common; 6, 

 scarce ; 9, very abundant ; 10, scarce ; 13, abundant ; 14, abundant ; 15, 

 common; 17, abundant; 18, abundant; 19, very abundant; 20, scarce; 

 21^ abundant; 22, common; 24, scarce; 25, common; 26, common. 



White niggerliead^ Quadrula coccinea {Conrad). — Although fairly 

 well distributed, having been collected tlirough nearly all the stretch 

 of river traversed, and at 14 different stations, Quadrula coccinea 

 does not appear to be common in the river. In all, 42 shells were 

 obtained. The greatest number taken at one place w^as 9, collected 

 at station 6. The shells are all rather small and moderately inflated. 

 The greater number have white nacre, though a few are pink. At 

 the pearler's camp it was called "white niggerhead." This species 

 probably really belongs to Pleurobema., as Ortmann has found the 

 outer gills only functioning as marsupia. It is, however, quite 

 variable and may include several species. I have never found the 

 common flat form gravid. An inflated form, identified as this, but 

 approaching somewdiat the shape of Q. solida^ was found gravid in 

 the Iroquois River and contained glochidia in only the outer gills. 

 Where the species attains a good development the wdiite-nacre shells 

 furnish very fair button material, but the rather dwarf shells of the 

 Big Buffalo River are of no commercial value. 



It was found at the following stations: 2, a few dead shells; 

 3, scarce; 4, scarce; 5, scarce; 6, common; 8, scarce; 9, scarce; 12, 

 scarce; 13, scarce; 15, scarce; 16, scarce; 17, scarce; 18, scarce; 21, 

 scarce ; 25, common. 



