[313] INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 19 
higher up toward high-water mark, and is comparatively rare. This is 
the Panopeus Harrisii. It can be easily distinguished, for it lacks the 
black on the ends of the big claws and has a groove along the edge of 
the front of the carapax, between the eyes. This last species is also 
found in the salt marshes, and was originally discovered on the marshes 
of the Charles River, near Boston. All the species of Panopeus are south- 
ern forms, extending to Florida, or to the gulf-coast of the Southern 
States, but they are rare north of Cape Cod, and not found at all on 
the coast of Maine. They contribute largely to the food of the tautog 
and other fishes. The lobster, Homarus Americanus, is sometimes found 
lurking under large rocks at low-water, but less commonly here than 
farther north, as, for instance, about the Bay of Fundy. In this region 
it lives also on sandy and gravelly bottoms, off shore, but in rather 
shallow water. It is an article of food for many fishes, as well as for 
man. Active and interesting little “hermit-crabs,” Hupagurus longi- 
carpus, are generally abundant in the pools near low-water, and con- 
cealed in wet places beneath rocks. In the pools they may be seen 
actively running about, carrying upon their backs the dead shell of 
some small gastropod, most commonly Anachis avara or Ilyanassa 
obsoleta, though all the small spiral shells are used in this way. They 
are very pugnacious and nearly always ready for a fight when two 
happen to meet, but they are also great cowards, and very likely each, 
after the first onset, will instantly retreat into his shell, closing the 
aperture closely with the large claws. They use their long slender 
antenne very efficiently as organs of feeling, and show great wariness 
in all their actions. The hinder part of the body is soft, with a thin 
skin, and one-sided in structure, so as to fit into the borrowed shells, 
while near the end there are appendages which are formed into hook- 
like organs by which they hold themselves securely in their houses, for 
these spiral shells serve them both for shields and dwellings. This 
species also occurs in vast numbers among the eel-grass, both in the 
estuaries and in the sounds and bays, and is also frequent on nearly all 
other kinds of bottoms in the sounds. It is a favorite article of food 
for many of the fishes, for they swallow it shell and all. A much 
larger species, belonging to the same genus, but having much shorter 
and thicker claws, (Hupagurus pollicaris,) isalso found occasionally under 
the rocks at low-water, but it is mach more common on rocky and shelly 
bottoms in the soundsand bays. Its habits are otherwise similar to the 
small one, but it occupies much larger shells, such as those of Lunatia 
heros, Fulgur carica, &c. This large species is devoured by the sharks 
and sting-rays. 
The Amphipods are also well represented on the rocky shores by 
a considerable number of species, some of which usually occur in 
vast numbers. These small erustacea are of great importance in con- 
nection with our fisheries, for we have found that they, together with the 
shrimps, constitute a very large part of the food of most of our more valu- 
