Vol. XLIV JULY, 19S0. No. 1
THE V.VRIATIONS OF APORRHAIS OCCIDENTALIS BECK
BY CHARLES W. JOHNSON
This interesting species presents considerable variation
throughout its range from the Georges Bank off Massachu-
setts to northern Labrador, in depths of water varying
from 6 to 120 fatlioms. Although naturally merging into
each other there are three quite distinct forms. One is
found along the coast of Maine and Nova Scotia, the second
along the coast of Labrador, while the typical form seems
to occupy the Gulf of St. Lawrence and the deeper waters
of the Gulf of Maine. In my list of mollusks from Labra-
dor, Newfoundland and Nova Scotia, collected by Mr. Owen
Bryant (1926), I gave to the coarse ribbed form from
Maine the varietal name of mainensis, considering those
from Labrador to be typical. Further study however shows
that these are also quite different from the typical form, in
fact, more so than the variety mainensis.
APORRHAIS OCCIDENTALIS (Beck). PI. I, fig. 1.
Rostellaria occidentalis Beck, Guerin's Mag, de Zool., 1836,
vol. 6, classe 5 (text) pi. 72.'
' Beck refers to a paper as follows: