THALESTEIS. 123 



seta towards the middle of the inner border ; in the 

 male the outer branch is much longer than the inner 

 (fig. 13), bearing three stout spines and two setae, 

 while the inner portion of the basal joint has only two 

 spines, one of which is very small. Caudal segments 

 as long as the last abdominal ring ; inner setse longer 

 than the abdomen, outer scarcely half that length. 

 The whole integument of the animal has a corrugated 

 or waved appearance, this being especially conspicuous 

 in the fifth pair of feet of the female. Length i^th 

 of an inch (1*8 mm.). 



A very fine and well-marked species, apparently 

 local in its distribution, but sometimes occurring in 

 moderate abundance. I have specimens from the 

 undermentioned localities : Westport Bay, Ireland, 

 taken in dredge and tow-net, but rare ; also in Kound- 

 stone and Clifden Bays ; Scilly Islands, dredged in ten 

 to twelve fathoms, and taken in the surface-net and 

 amongst weeds at low water; dredged in a depth of 

 five fathoms at Oban, and found also on the fronds of 

 Laminaria at Tobermory (Rev. A. M. Norman). 



2. THALESTRIS HELGOLANDICA, Glaus. PI. LXI, figs. 



914. 



TJialcstns helgolandica, Claua. Die frei lebenden Copepoden, 

 p. 131, t. xvii, figs. 1221 (1863). 



Body robust ; abdomen short ; rostrum broad and of 

 moderate length. Anterior antenna (fig. 9) elongated, 



