78 
THE + CONCHOLOGISTS’ : EXCHANGE 
185. Planorbis (Gyraulis) hirsutus, 
Gould. 
Synonyms: Planorbis albus, W. G. Binney, 
Haldeman, non Miiller. 
Shell light brown, concave on both sides, 
more so on the left, whorls ¢hree, rapidly in- 
creasing; aperture large, sub-oval, oblique; lip 
simple. Diameter one-quarter of an inch. 
The prominent characteristic which distin- 
guishes this species from all others of the sub- 
genus, is that expressed by its specific name, 
hirsutus. The entire surface of the shell is 
covered by: a dark epidermis, bristling with 
rigid hairs which are arranged in close revoly- 
ing lines. When the shell becomes bleached 
the hairs drop off and show plainly the revolv- 
ing lines. 
Mr. W. G. Binney has endeavored to show 
that our shell is identical with the Planorbis 
albus, Miiller, of Europe, and in his description 
of American fresh-water shells in the ‘ Smith- 
sonian Miscellaneous Collection,’ No. 143, 
1865, page 132, he has named it Planorbis 
albus, Miiller. Notwithstanding Mr. Binney’s 
great reputation as a Conchologist, aud his 
valuable labors in this department, I cannot 
but think he is wrong in this instance. The 
two species, hirsutus and albus are as surely 
distinct as any two species of the same sub- 
genus can be. ‘The general form of the two 
is similar, but not more so than several other 
species. The color of the European species, 
albus, is, as its name signifies, white, or nearly 
so, and they have neither the rigid hairs, nor 
the revolving lines of our hirsutus. I have 
numerous specimens of both species, and my 
specimens of albus are not as smooth as de- 
flectus or parvus. The number of whorls and 
the umbilicus are different, and the habits of 
the animal are unlike ours. 
On referring to Reeve’s ‘British Land and 
Fresh-water Mollusks,”’ page 139, we find his 
description of Planorbis albus: ‘Shell rather 
depressed, thin, whitish, horny, covered witha 
scarcely perceptible hairy epidermis: lower, 
concavity, a broadly excavated umbilicus; 
whorls four to five. The animal feeds vora- 
ciously on species of Potamogeton and is found 
( 
on water plants in all parts of the British 
Isles.’ 
Planorbis hirsutus was first discovered by 
Prof. C. B. Adams, in Mansfield, Mass., and 
described by Dr. A. A. Gould, in 1840, in 
“Silliman’s Journal,’ Vol. XXXVIII, page 
196, and in 1841, in “Gould’s Invertebrata of 
Massachusetts,’ page 206. It has been found 
at Dorchester, Dedham and Cambridge, adher- 
ing to sticks and stones in stagnant water, and 
in Rhode Island at Valley Falls and in the 
Providence and Worcester Canal, on stones, 
but has never been found in America, so far 
as I can learn, upon a water plant. 
To be Continued. 
Young Collectors’ Comer. 
HOW TO COLLECT SMALL LAND 
SHELLS. 
BY V. STERKI, M. D., NEW PHILADELPHIA, O. 
Continued. 
Il. 
HOW TO TREAT THEM WHILE ON JOURNEYS. 
Many American collectors recommend put- 
ting the smaller specimens in alcoho] at once. 
This is very expedient but it does not prove 
quite satisfactory for several reasons. In many 
instances it is desirable to examine the living 
animal; its size, shape, color, and mode of 
locomotion. In the case of rare or new 
forms this is of great importance and would not 
be possible after immersion in alcohol, which 
has a tendency also to coagulate slime and so 
stiffen the odontophore (lingual membrane), as 
to render its examination difficult. By simply 
