140 THE NAUTILUS. 



P. negledum Auth. Cited by Miles and DeCamp. Mr. Streng 

 has kindly sent me specimens from Grand River, Kent County, 



P. elevatum Say. Grand River, Michigan, received from Mr. 

 Streng. 



P. lahiaium Lea. Cited by DeCamp. 



B. pallidum Lea. Cited by DeCamp. 



Goniobasis livescens Mke. Very common and considerably sub- 

 ject to local variation. 



G. livescens cuspidatiis Anth. This form occurs abundantly in the 

 Maple River, Clinton County, where it was collected by- Dr. Leach. 

 Cited by DeCamp from Kent County, and collected by Streng at 

 Berlin, Ottawa County. 



Goniobasis Milesii Lea. Huron River, Ann Arbor, Michigan. 

 This form originally described from Tuscola County specimens, is 

 probably a local variety of the preceding species. 



G. translucens Anth. Grand River, Kent County, collected by 

 DeCamp. It is doubtful whether this species is more than a banded 

 variety of G. livescens Mke. 



G. brevispira Anth. Collected at Mono Lake, Muskegon by Dr. 

 DeCamp and identified by Pilsbry. 



G. pulchella Anth. Cited by Miles and DeCamp. 



G. gracilior Anth. Cited by DeCamp from Round Lake, Peto- 

 sky, Michigan. 



G. Niagarensis Lea. Cited by Miles. 



G. Virginica Gml. Cited by Sager and Miles. Clearly an error 

 as the species does not occur west of the AUeghanies. As P. sub- 

 idare is not given in either of these lists, it seems probable that 

 that is the species referred to. 



Unio alaius Say. Southern part of the State. Muskegon is the 

 most northern locality known to me. Specimens from the Detroit 

 river are but half the size of those from the Rouge river, one of its 

 tributaries in Wayne County. The same dwarfing effect of the 

 colder water of the Detroit river is noticeable in nearly all of the 

 species found there. 



Addenda. 



On page 66, line 14, for S. partinneium Prime, substitute /S. Jat/aii- 

 um Prime, and add the following: 



