Kentucky Mollusk Distributions 143 



of this family of snails. Distributional data for lymnaeids in Kentucky 

 are sparse to lacking, particularly in the western half of the state. 



Lymnaea columella Say. Collections: 21 (4), 44 (4). The specimens 

 were taken from backwaters over mud bottoms, and most of them were 

 heavily laden with fluke larvae. 



Lymnaea palustris (Muller). Collections: 28 (3). Although the occur- 

 rence of this pond snail in Kentucky was implied by Baker (1911), this is 

 the first record of its occurrence supported by definite locality data. 



Lymnaea stagnalis Linnaeus. Collections: 28 (5). The pond from 

 which these specimens were taken supports a large community of cool- 

 water vegetation and attracts many migratory aquatic birds, which may 

 account for the rather speciose snail population at this station. Aquatic 

 snails, particularly young specimens, are easily transported in mud and 

 plant debris on the feet of these birds. This species was heretofore 

 unknown from Kentucky. 



Lymnaea humilis Say. Collections: 3 (1), 28 (1), 29 (1). This is by 

 far the most commonly encountered pond snail in Kentucky. The spec- 

 imen from Station 3 is of the obrussa form. 



Physidae 



This family is badly in need of comprehensive monographic treat- 

 ment. Many of the so-called species are doubtless ecotypes, and still 

 other species probably await discovery by means of electrophoretic and 

 other biochemical techniques. Identifications based on shell features 

 alone, such as the three species reported here, are only tentative. 



Physa heterostropha (Say). Collections: 22 (1), 28 (2). 



Physa gyrina Say. Collections: 32 (5). 



Physa Integra Haldeman. Collections: 22 (3), 25 (3), 29 (23). 



Ancyloplanorbidae 



We follow Hubendick (1978) in assigning this family name, which 

 includes the Planorbidae and the Ancylidae. 

 Bulininae: Physastrini 

 Ferrissia rivularis (Say). Collections: 44 (3), 45 (1). The specimens 

 were removed from dead unionid valves in deep, swift riffles. 

 Bulininae: Camptoceratini 

 Helisoma anceps (Menke). Collections: 15 (1), 17 (2), 20 (6), 28 (2), 

 29 (17), 42 (1), 43 (1), 50 (1). In the eastern highlands of Kentucky, 

 Helisoma anceps appears to be more common and abundant than the 

 following species. 



Helisoma trivolvis (Say). Collections: 21 (5), 22 (1), 25 (1), 28 (1), 

 29 (12), 47 (7), 48 (2). The principal habitats of this widespread species 

 are lowland, mostly in vegetated backwaters over mud bottoms. 

 Planorbinae: Planorbini 



Gyraulus parvus (Say). Collections: 29 (1). There are very few 



