[337] INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 43 
they pick up the bits of alga very daintily ; the females use indifferently 
either of their small claws for this purpose. They always swallow more 
or less sand with their food. Mr. Smith also saw these crabs engaged 
in scraping up the surface of the sand where covered with their favorite 
alge, which they formed into pellets and carried into their holes, in the 
same way that they bring sand out, doubtless storing it until needed 
for food, for he often found large quantities stored in the terminal 
chamber. Mr.T. M. Prudden has since ascertained that one of the other 
species of “ fiddlers” on our shores (G. minax) is also a vegetarian and 
feeds upon similar algee, which grow on the muddy salt-marshes. 
The Ocypoda arenaria is a crab allied to the “ fiddlers” and similar in 
some of its habits. It is a southern species, ranging as far as Brazil, 
and adult specimens have not yet been observed on the coast of New 
England, but Mr. Smith has observed the young in abundance at Fire 
Island, and we have the young from Block Island; it occurs at Great 
Egg Harbor, New Jersey, of larger size, and therefore it may be looked for 
onthe beaches of Nantucket and Martha’s Vineyard. This crab lives on 
the beaches at, and even far above, high-water mark. It digs large holes 
like the fiddlers, often in the loose dry sand, back from the shore, yet 
when disturbed it will sometimes take to the water in order to escape. 
though it soon returns to the shore. In digging its holes, according to 
Mr. Smith’s observations, it works in the same way as the “fiddler- 
crabs,” except that it is quicker in its motions, and often, instead of car- 
rying the pellets of sand to a distance from the hole, it throws it away 
with a sudden and powerful jerk, scattering the sand in every direction, 
It is eyen more cautious in its movements, andis always on the alert, even 
the slightest movement on the part of one who is watching them is 
sure to send them all into their holes instantly. In color this species 
imitates the sand very perfectly, especially while young, when they 
are irregularly mottled and speckled with lighter and darker shades of 
gray. They also have the habit of crouching down closely upon or 
into the sand, when suddenly frightened, and aided by their colors will 
often thus escape observation. At other times they will trust to their 
speed and scamper over the sand with such swiftness that they are not 
easily captured. This crab is carnivorous in its habits and, according 
to Mr. Smith’s observations, it lives largely upon the ‘“ beach-fleas” 
(Talorchestia) which inhabit the same localities. It will lie in wait and 
suddenly spring upon them, very much asa cat catches mice. It also 
feeds upon dead fishes and other animals that are thrown on the shore 
by the waves. 
Another inhabitant of the upper part of the sand-beaches, just below 
high-water mark, is the Scyphacella arenicola SmitH, which has, as yet, 
been found only on the coast of New Jersey, but probably occurs far- 
ther north. It is a small, sand-colored Isopod crustacean, which has no 
near relatives, so far as known, except in New Zealand. It burrows in 
the sand, making a little conical mound around the mouth of the holes. 
5v 
