40 



dently migrated from the eastern rivers, by the 

 canals, to Lake Erie, and from there over the 

 divide (Summit Co., ,(Jhio) by way of the 

 Ohio canal, then into the Tuscarawas river. 



129. Unio cylindricus Say. River, rare. One large 



and well formed specimen has none of the 

 characteristic prominences along the um- 

 bonal ridge. Another is aberrant in color- 

 ation, having crowded, fine, dark green inter- 

 mixed with few light green radial lines, and 

 showing nothing of the characteristic pointed 

 markings. 



130. Unio metanever Raf. var wardii Lea. Sugar 



Creek and race on some at Canal Dover. Not 

 a trace was found in the river. 



131. Unio phaseolus Hildr. Common in the river and 



Sugar Creek, attaining a large size. The 

 shell is very thick and heav}', comparatively. 

 In the female, there is a deep, oblique sulens 

 on the inner surface of each value, correspond- 

 ing with the unlutninous outer branches. 



132. Unio irroratus Lea, Common in the river; nacre 



white to rose colored. 



133. Alasmodonta pressa Lea. (U. pressus). River 



and Ohio Canal, scarce. 



134. Alasmodonta rugosa Barnes. (Margaritona 



rugosa). Common in the river; Sugar Creek; 

 scarce in the canal. 



135. Alasmodonta complanat'd. Barn. Scarce and 



small in the river. Common and quite large 

 in the Ohio Canal. Still water Creek. 



136. Alasmodonta marginata Sa\'. River, rather 



common. 



137. Alasmodonta delioidea Lea. River and Ohio 



Canal, rather common. 



138. Alasmodonta hildrethiana Lea. River, quite 



scarce. 



139. Alasmodonta dehiscens Say. River, rather 



scarce. 



