166 BRITISH OOPEPODA. 



1. POEOELLIDIUM TENUICAUDA, CldUS. PI. LXIX, figS. 10 



13; PI. LXX, fig. 5. 



Porcellidium tenuicauda, Clans. Beitrage zur Kenntniss der 



Entomostraken, 1 Heft, p. 6, 

 taf. 2, figs. 1018 (1860). 

 Die frei-lebenden Gopepoden, 

 p. 140 (1863). 



First segment not quite half the length of the body ; 

 caudal segments acutely pointed behind, the two toge- 

 ther forming a heart-shaped lamina. Anterior antenna 

 6-jointed ; last two joints very short. Outer branch 

 of the second foot only as long as the first joint of the 

 inner branch. Fifth pair of feet large, triangular, 

 reaching as far as the extremity of the abdomen, very 

 wide at the base, acutely pointed behind, divided 

 longitudinally by a rib-like, curved line; margins 

 finely ciliated ; a single short seta near the middle of 

 the outer margin. Integument thick and marked 

 with thickly-set small circular impressions. Colour 

 yellowish, the central portion of the body often 

 tinged with deep crimson. Length Ysrd of an inch 

 (1-1 mm.). 



Of rare occurrence. I have not seen more than 

 half a dozen specimens, most of which were found 

 amongst Laminarice in the west of Ireland : Birtirbuy, 

 Clifden, and Ventry Bays. One specimen dredged off 

 St. Agnes (Scilly), in a depth of ten fathoms. 



