370 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



The Mysis stenolepis Smith, (Plate III, fig. 12, female,) is often very 

 abundant in such situations. The small young ones have been taken in 

 May, and the half-grown ones later in the season. In the early spring 

 the adult females, with eggs, occur in great numbers among the eel- 

 grass, in estuaries and ponds. Mr. Vinal S". Edwards caught a large 

 number in a small pond at Wood's Hole, April 1. No males were found 

 at this time with the females; the only adult males observed were taken 

 in autumn. Possibly the males do not survive the winter. The adult 

 females have not been observed in summer, and they probably die after 

 hatching their young in the spring. The whole body is translucent; 

 each segment of the body has a stellate black spot; and there is more 

 or less blackish pigment on the caudal lamellae, telson, antennal scales, 

 and inner flagellum and peduncle of the antennulae. This species con- 

 tributes largely to the food of many fishes. The other species, M. Amer- 

 icana Smith, also lives among eel-grass, as well as in deeper water off 

 shore among algae. This has been found in large numbers in the stom- 

 achs of the shad and the spotted flounder. 



Of Amphipods there are comparatively few species. The Unciola 

 irrorata (p. 340, Plate IY, fig. 19) is pretty common here, as elsewhere. 

 The AmpMthoe valida Smith (p. 315,) is often met with among eel- grass. 

 Another species, A. compta Smith, also occurs in the same places. 

 It differs from the preceding in many characters, but may easily be dis- 

 tinguished by its red eyes. A third species of the genus, A. longimana 

 Smith, is also found among eel-grass. It has black eyes. The Coro- 

 phium cylindricum and Gammarus muoronatus occur among eel-grass and 

 algae,, often in great numbers. 



Of Isopods there are several species. The Idotea irrorata (p. 316, 

 Plate V, fig. 23) is common wherever eel-grass is found. The Erichso- 

 nia attenuata Harger, (Plate VI, fig. 27,) is also found clinging to 

 eel-grass in muddy situations. The Epelys trilobus (Plate VI, fig. 28) 

 is found creeping about over the bottom or among and beneath the 

 decaying vegetable matter and mud usually to be found in sheltered sit- 

 uations. It is usually so covered up with adhering dirt as readily to 

 escape observation. The Epelys montosus also occurs in similar situa- 

 tions. 



Whenever lumber or drift-wood has been left for some time on the 

 muddy shores it is found to be more or less eaten by the Limnoria lig- 

 noram, (Plate VI, fig. 25.) This small isopod gnaws its galleries in the 

 wood to a depth of about half an inch from the surface, and after a 

 time these galleries become so numerous that the superficial layer will 

 be completely honey-combed, and it will then scale off and another layer 

 will be attacked. This little creature often does great damage to the 

 piles of wharves and other kinds of submerged wood-work in this re- 

 gion, and will be mentioned again in discussing the animals inhabiting 

 piles, &c. 



The "horse-shoe crab," Llmuhis Polyphemus, (p. 340,) is also common 



