THE NAUTILUS. 55 



P. dilatm Hal J. = dilatatw Gld. 



P. elevatus Adams = dilatatits Gld. 



Paltidina hyalina Lea = exaeutus Say. 



P. lens Lea = exaeutus Say. 



P. lenticularis Lea = exaeutus Say. 



P. obliqitus DeKay = defectus Say. 



P. planulatug Cooper = opercularis Gld. 



P. umbilicatas Taylor (not Mull.) =wnbilicatellus Cockerell. 



P. vermiculnris Gld. =parrus Say. 



P. virens Adams dilatatus Gld. 



P. hirsutns Gld. differs from the European albus Miill. in having 

 the hairs longer and in fewer rows. 



P. costatiis DeTarr & Beecher, never having been reported from 

 any locality hut Michigan, is very likely introduced specimens of 

 P. nautileus var. cristatm Drap., with which it seems identical. 



P. alabamensis Pilsbry shows light spiral striations under a lens. 



In P. sampsoni Ancey, the spiral striation is quite distinct. 



GENERAL NOTES. 



WE have taken advantage of the mid-summer number when 

 Conchologists, like everybody else, avoid all the desk work they can, 

 to insert an Index to the Conchologist' 's Exchange. This will afford 

 malacologists an opportunity of ascertaining the contents of that 

 periodical, now rare and out of print. We had hoped to reprint the 

 Exchange in full, but a sufficient number of subscriptions has not 

 been received to justify us in the outlay. 



SEVERAL years ago I collected two young specimens of a delicate 

 bivalve in a mud bank at Revere, Mass., and put them away labeled 

 Zirphcm crispata. I lately discovered that they are Pholastruncata> 

 which shell has not, to my knowledge, been previously reported from 

 north of Cape Cod. EDWARD W. ROPER. 



MR. A. A. HINKLEY, who has been for some time in Roekford, 

 111., has returned to DuBois, 111. 



THE Chicago Academy of Sciences has recently purchased of Mr. 

 John Walton, of Rochester, his collection of Oyprcridcs. It has also 

 purchased one of the collections of California and Mazatlan shells, 

 prepared by Dr. P. P. Carpenter, and numbering some 3000 species. 



