38 



SYNOPSIS OF 



H 



o 



>-y o 



Ph 



o 



WIPE. 



tenuissimus. /yCa. 



Symp. tenuissima. Lea, in Trans. Am. P. S. 

 An. purpurasccns. Swain. 

 Unio velum. Say. 



bilineatus. Lea. Ben. 



Symp, bilineata. Lea., in Trans. Am. P. S. 



Corrianus. I^ea. 



phaseolus. Hild. Eat. 

 Unio planulatus. Lea. 

 Unio cuneatus.* Barn. (White var.) 



arcus. 



Coi 



arctatus. Con. 



gibbosus. Bar. Eat. Hild. 

 Unio mucronatus. Bar. 

 Unio nasuta. Lain. 

 Unio dilatata? Raf. 

 Unio dilatatus. Con. 



however, of subrostratus does not apply to my iris, and certainly this shell 

 could not have been under his eye when his description was made. He says 

 that the subrostratus " may be said to be the analogue of the Unio nasutus 

 (nobis) of the western waters." As the U. nasutus inhabits the western 

 waters a variety of that species may have been described by him for subros- 

 tratiis. 



* In note to Dr. Hildreth's Memoir on the shells in the vicinity of Mar- 

 rietta, Ohio, published in Silliman's Journal. 



