Oo 
or 
THE NAUTILUS. 
P. dilatus Hald. = dilatatus Gld. 
P. elevatus Adams = dilatatus Gld. 
Paludina hyalina Lea = exacutus Say. 
P. lens Lea = exacutus Say. 
P. lenticularis Lea = exacutus Say. 
P. obliquus DeKay = deflectus Say. 
P. planulatus Cooper = opercularis Gld. 
P. umbilicatus Taylor (not Mill.) = umbilicatellus Cockerell. 
P. vermicularis Gld. = parvus Say. 
P. virens Adams = dilatatus Gld. 
P. hirsutus Gld. differs from the European albus Mill. in having 
the hairs longer and in fewer rows. 
P. costatus DeTarr & Beecher, never having been reported from 
any locality but Michigan, is very likely introduced specimens of 
P. nautileus var. cristatus 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 
Zirphea crispata. I lately discovered that they are Pholas truncata, 
which shell has not, to my knowledge, been previously reported from 
north of Cape Cod.—Epwarp W. Roper. 
Mr. A. A. Htnkuey, who has been for some time in Rockford, 
Ill., has returned to DuBois, Il. 
THE Chicago Academy of Sciences has recently purchased of Mr. 
John Walton, of Rochester, his collection of Cypreide. It has also 
purchased one of the collections of California and Mazatlan shells, 
prepared by Dr. P. P. Carpenter, and numbering some 3000 species. 
