1 66 HOLMES. [VOL. II. 



net over the eel-grass. It is abundant during the summer 

 months, a period when most of the other species of amphipods 

 suffer a marked diminution in numbers. It is quite hardy, and 

 may be kept alive for months in small glass dishes, if they are 

 kept covered and the sea water kept fresh by a small piece of 

 Ulva. Observations on this species were carried on for nearly 

 three months. Specimens were kept isolated in small dishes 

 and daily observations made and recorded. I was thus able to 

 follow the histories of quite a number of individuals for a 

 considerable period. 



Specific Description. 



Body slender. Eyes round. Lateral lobes of the head 

 truncated in front. Antennules slender, about as long as the 

 body, the second segment a little longer, but much more 

 slender than the first ; third segment from one-third to one- 

 half the length of the second ; flagellum much longer than the 

 peduncle. Second antennae shorter than the first, but usually 

 with a longer peduncle ; last segment of the peduncle a little 

 longer than the preceding one; flagellum shorter than the two 

 preceding basal joints. 



Second, third, and fourth epimera much longer vertically 

 than wide ; fifth epimeron about as long as the fourth, but 

 broader and excavated at the upper posterior angle ; lower 

 margins of the epimera furnished with very short setae. 

 Postero-lateral angles of the abdominal segments not acute. 



First gnathopods in the male elongated, the first joint pro- 

 duced into a rounded lobe at the antero-distal angle ; carpus 

 narrow, nearly as long as the hand, and thickly setose on the 

 posterior margin ; hand very long and narrow, slightly incurved, 

 and of nearly the same width throughout, although slightly 

 widened near the base ; lower margin setose ; palm very short, 

 transverse, and rounded at the outer angle ; dactyl very large, 

 dentate, and projecting far beyond the palm when closed. 

 Second gnathopods much stouter than the first ; first joint with 

 a rounded lobe at the antero-distal angle ; hand much broader 

 and stouter than in the first pair ; palm oblique, with a deep 



