THE MUSEUM 
IHE UROOKLYX IXSTITVTE OF ARTS AND SCIENCES 
lENCE bulle: 
VOL. 2, NO. 2. 
LONG ISLAND FAUNA AND FLORA— II. 
A LOXG ISLAXD ACMAEA. AXD A XEW" WVRIETY OF 
UROSALPINX CINEREA. 
Acmaea fergiisoni sj). iio\ . 
Shell patelliform. outer surface gray or greenish, eroded almost 
to the jnargin, below the eroded area sometimes plain, sometimes mot- 
tled with reddish brown on a pale background; base oval, altitude more 
than two-fifths of the mean diameter; apex laterally compressed, blunt, 
directed forward, between three and four-ninths of the entire length 
behind the anterior margin ; sculpture consisting of fine concentric lines 
with an occasional coarse undulation, and of fine, irregularly spaced, 
radiating wrinkles, the latter often obsolete or entirely wanting, always 
more distinct on the posterior half; anterior slope straight, incurved 
under the apex in perfect specimens ; posterior slope convex ; aperture 
oval, coextensive with the base, widest behind the middle; margin 
simple, sharp, with all points in the same plane; within polished, 
moderately thickened, when fully matured heavily thickened immediateh" 
below the scar; color varying from pure white through tints of rose 
or blue to dark mahogany or blue-black, rarely unicolored, generallv 
either mottled or with several shades arranged in zones, the center and 
the margin usually darker; cicatrix continuous, very narrow over the 
head, widened upward at the neck. 
Foot large, orbicular, white, the dark visceral mass faintly showing 
through it at the center ; a white collar of muscle extending upward from 
the foot through the mantle and adhering to the shell, mantle thin, 
greenish, apiculate at the margin, completely encircling the animal : 
tentacles subulate, long, white; a small black eye-spot on the outer side 
of the base of each tentacle ; ctenidium slender, plume-like, attached by 
one end in the ca\ity above the neck and extended more than half the 
length of the body down the right side between the foot and the mantle. 
17 
