IDOTEA EMARGINATA. 387 
Our figures of this species are derived from Dr. Leach’s 
largest specimen, preserved in the British Museum (No. 
1,000). It is very closely allied to JI. fricuspidata, the 
chief difference being that the central point of the ex- 
tremity of the tail (of which a very slight trace may be 
observed in certain individuals) does not extend so far 
back as the prolonged lateral angles, and the epimeral 
scales (coxa) of the six hind pairs of legs are widely 
developed on the dorsal surface of the body, which is 
covered with minute dark-coloured dots, 
The basal segments of the tail are also formed as 
in J. tricuspidata, but the lower pair of antennez are 
comparatively shorter. 
Various specimens, captured in different parts of the 
British coast by Col. Montagu and Dr. Leach, are con- 
tained in the British Museum. 
Mr. Robertson has sent it to us from Cumbray, and 
the Rev. A. M. Norman from the coasts of Durham and 
Northumberland. 
It has also been taken at Port Patrick and Dundrum, 
Ireland, by the late Mr. W. Thompson. Mr. W. P. 
Cocks found this species among trawl refuse of fishing 
boats, also in the stomach of fish at Falmouth. It is 
common among weeds all round the coasts of Europe. 
