140 Branley A. Branson and Donald L. Batch 



sphaeriids and 6 families, 12 genera and 22 species of aquatic snails. The 

 number of specimens obtained at each site is provided in parentheses 

 following the collecting site number. All specimens were deposited in 

 the Museum of Zoology, Eastern Kentucky University. 



Bivalvia: Sphaeridae 



The characters used by Clarke (1973) and Burch (1975) to separate 

 Sphaerium and Musculium demonstrate as many relationships as they 

 do differences. Hence, we follow Herrington (1962) in relegating the 

 genus Musculium to subgeneric status under Sphaerium. 



Sphaerium corneum (Linnaeus). Collections: 48 (1). The habitat 

 consisted of fine sand admixed with small quantities of silty materials. 

 Considered an exotic by Herrington (1962), this species heretofore has 

 not been reported from Kentucky waters. A single specimen is not very 

 conclusive evidence, particularly because aberrant specimens of S. ni- 

 tidum Westerlund are easily confused with this species. Additional field 

 work needs to be accomplished in order to ascertain the status of S. 

 corneum in Kentucky. 



Sphaerium lacustre (Muller). Collections: 28 (4). Specimens were 

 obtained by dredging. The distribution of this and other pond-dwelling 

 sphaeriids is poorly known in Kentucky, principally because of inade- 

 quate sampling. 



Sphaerium fabale Prime. Collections: 1 1 (2), 31 (12), 43 (3), 46 (15), 

 49 (1). This species is not uncommon in clean upland tributaries and 

 main rivers in relatively shallow situations with an abundance of rocks 

 and gravel. Branson and Batch (1981 and 1982) reported thriving popu- 

 lations of this small clam in Dix and Red rivers, both major tributaries 

 of the Kentucky River. 



Sphaerium simile Say. Collections: 8(1), 1 1 (1), 14 (10), 32 (2). This 

 rather heavy-shelled form is not uncommon in the Kentucky River 

 drainage (Branson and Batch 1981), but apparently is scarce in most of 

 the Licking River. 



Sphaerium striatinum (Lamarck). Collections: 13 (1), 22 (3), 33 (1), 

 37 (1), 39 (1), 42 (5), 44 (1), 45 (1), 48 (22), 49 (1), 50 (2). The most 

 widespread and abundant sphaeriid in Kentucky, this species sometimes 

 produces prodigious populations in clean (lacking silt), rocky, vegetated 

 riffles. 



Sphaerium transversum (Say). Collections: 29 (6). This species was 

 taken in dredge samples from soft mud in water approximately 2 m 

 deep. 



Pisidium compressum Prime. Collections: 28 (1), 29 (3). Both col- 

 lections came from mud-bottom ponds. All members of the genus Pi- 

 sidium are poorly known in Kentucky because of a dearth of collecting. 



