74 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [368] 



numbers in the somewhat brackish waters of estuaries and the mouths 

 of rivers. The young specimens of all sizes, up to two or three inches 

 in breadth, are, however, very frequent along the muddy shores, hid- 

 ing in the grass and weeds or under the peaty banks at high- water, and 

 retreating as the tide goes down; when disturbed they swim away 

 quickly into deeper water. They also have the habit of pushing them- 

 selves backward into and beneath the mud for concealment. They are 

 predacious in their habits, feeding upon small fishes and various other 

 animal food. They are very pugnacious and have remarkable strength 

 in their claws, which they use with great dexterity. When they have 

 recently shed their shells they are caught in great numbers for the 

 markets, and these " soft -shelled crabs" are much esteemed by many. 

 Those with hard shells are also sold in our markets, but are not valued 

 so highly. This crab can easily be distingushed from all the other 

 species found in this region by the sharp spine on each side of the 

 carapax. 



The common " spider-crab," Libinia canaliculata, (p. 339,) is very com- 

 mon on muddy shores and flats. It hides beneath the surface of the 

 mud and decaying weeds or among the eel-grass, and is very sluggish 

 in its motions. Its whole surface is covered with hairs which entangle 

 particles of mud and dirt of various kinds ; and sometimes hydroids, 

 algae, and even barnacles grow upon its shell, contributing to its more 

 ready concealment. The males are much larger than the females, and 

 have long and stout claws. They often spread a foot or more across the 

 extended legs. The females have much smaller and shorter legs and 

 comparatively weak claws. 



Another similar species, Libinia dubia, is also found on muddy shores 

 and has nearly the same habits. It has a much longer rostrum, more 

 deeply divided at the end. 



The two common species of u hermit-crabs" are both found on muddy 

 shores, especially among eel-grass, but the larger one, Eupacjuriis polli- 

 caris, (p. 313,). is comparatively rare. The small one, E. longicarpits, (p. 

 313,) is very common and usually occupies the dead shells of llyanassa 

 obsoleta, though many may be found in other species of shells. 



The Gebiaaffinis (Plate II, fig. 7) isa crustacean somewhat resembling a 

 young lobster three or four inches in length. It lives on muddy shores 

 and digs deep burrows near low- water mark, in the tenacious mud or clay, 

 especially where there are decaying sea- weeds 'buried beneath the sur- 

 face. The burrows are roundish, half an inch to an inch in diameter, 

 very smooth within, and go down obliquely for the distance of one or 

 two feet, and then run off laterally or downward, in almost any direc- 

 tion, to the depth of two or three feet, and are usually quite crooked 

 and winding. We have found them most abundant on the shore of 

 Great Egg Harbor, New Jersey, near Beesley's Point, but they also 

 occur at New Haven and Wood's Hole, &c. This species is quite active ; 

 it swims rapidly and jumps back energetically. It is eagerly devoured 



