37 



97. Amnicola cincinnatiensis Anth. Ohio Canal, 



rare. 



98. Pomatipsis lapidaria Say. Common in some 



places, as a rule away from water. 



99. Bithynella obtusa Say. Ohio Canal, rather rare. 



100. Pleurcera labiatum Lea. River, rare. 



101. Goniobasis livescens Mke. " var lithasisides 



Lea". River, abundant. 



102. Goniobasis gracilior Anth . var. — River, common 



and variable. 



103. Goniobasis depygis Say. Little Still-water 



Creek. 



104. Valvata tricarinata Say. Common. 



105. Unio ligamentinus Lam. River, abundant; in 



many places outnumbering all other 

 Unionidae combined. Rather variable in 

 size, shape and color. One specimen was 

 found in the canal. 



106. Unio rectus Lam. Not common in the river; 



large; one specimen, female, is 184 milimeters 

 long. The nacre is purple colored in the 

 young, white in the adult. 



107. Unio luteolus Lam. Common in the river and 



Creeks, large and beautiful in the Ohio Canal. 

 Prefers quiet water and muddy bottom. A 

 coarse, short form, very much inflated and 

 badly eroded, in the Little Stillwater Creek. 



108. Unio ventricosus Barnes. (U sulesvatus Lea, the 



male. U. occidens Lea, the female.) Rather 

 common in the river, attaining a large size. 

 Ill some, the nacre is rose colored. One shell 

 has three large, well formed cardinal teeth in 

 each valve. An interesting observation has 

 been made on a large female specimen. Being 

 under about ten inches of quiet, clear water, 

 the posterior, prodruding parts of its mantle 

 flaps were widely expanded and regularly 

 undulating, waving, probably for the purpose 



