126 BRITISH COPEPODA. 
slightly produced and, armed with three spine-like— 
sete; second joint triangular, beset with five or six 
sete on the outer, and one near the apex of the inner 
margin, First two joints of the abdomen (fig. 9) very 
wide and fringed with small cilia; the second joint 
produced downwards into two broad triangular pro- 
cesses (0b), third joint forming two similar but smaller 
projections (¢ c); all the abdominal joints, as well as 
the caudal segments, very short and broad. Length 
g5th of an inch (1 mm.). Colour yellowish, more or 
less banded with deep crimson, the parts of the body 
which exhibit the colouring being usually the second 
and third thoracic segments and two or three of the 
median joints of the upper antenne, but the bases of 
the limbs, tail, &c., are hable to partake in the red 
colouring. 
This is a widely distributed species, and sometimes 
occurs in considerable abundance; it is readily dis- 
tinguished from all other species of Thalestris by the 
aculeate character of the spines of the swimming-feet. 
It has occurred sparingly in dredgings from the coast 
of Durham and Yorkshire—off Marsden, ten fathoms, 
Hawthorn, twenty-seven fathoms, and Red Chiff, thirty- 
five fathoms; Scilly Islands, ten to twelve fathoms, 
and also on algz in Porcressa Bay, St. Mary’s; 
dredged off Cumbrae and Portincross, Firth of Clyde ; 
Port Dinlleyn, North Wales; Clew Bay and Lough 
Swilly, Ireland; plentiful on fronds of algz in Mulroy, 
Clifden, Birtirbuy and Ventry Bays; Oban (fev. A. 
M. Norman). 
