334 



walker: shells of MICHIGAN. 



where it was found nearly twenty years ago. 



Unio gracilis Bar. 



U. iris Lea. Sager, Miles, Currier. This species is of 

 rather questionable occurrence in this state. It appears in all the 

 lists, but has probably been confounded with U. Novi-Eboraci, 

 a closely allied species. 



U. laevissimus Lea. 



U. Leibii Lea. I obtained a single specimen of this rare 

 species several years ago from the Detroit river. 



U. ligamentinus Lam. 



U. luteolus Lam. 



U. multiradiatus Lea. 



U. nasutus Say. 



U. Novi-Eboraci Lea. 



U. occidens Lea. 



U. penitus Con. Sager, Miles. A southern species and 

 evidently an error in identification. 



U. perplexus Lea. The form of this species found in the 

 Detroit river has been described as var. perobliquus by Conrad in 

 his Monograph. 



U. phaseolus Hild. 



U. pustulatus Lea. 



U. pustulosus Lea. Sager, Miles. 



U. radiatus Lam. Cited by Currier as U. distans Anth. 

 Anthony's species was from Ohio and is referred to radiatus by 

 Mr. Lea. 



U. Rangianus? Lea. Several years ago I found a single 

 female specimen in the Detroit river, which has been referred to 

 this species. The identification is not my own and may be 

 doubtful. 



U. rectus Lam. Two forms of this species from Michigan 

 waters have been described as distinct. One from the Detroit 

 river as U. Sageri by Conrad and the other from Livingston 



J.C, ii., Nov., la:!) 



