1912.] R. B. SEYMOUR-SEWELL: Surface-Living Copepoda. 339 
pod of the 5th pair of legs is simple and resembles that present 
in C. typicus. 
@? Total length rz mm. 
The head and thorax are as inthe female; the abdomen consists 
of four segments and the fureal rami are symmetrical as in the 
female. 
The grasping antenna has the knee-joint, as usual, between 
the 18th and rgth segments and the proportional lengths of the 
distal joints are as follows :— 
Dae UAC aL 5 el On Li 7a US O=2 ime 22/213 a2 ie 
Tiqierie 20820020) 420 a2 O OL? 
The roth, 11th and 12th segments all bear a curved spine-like 
process on the anterior surface. The 17th segment bears a 
toothed-plate which is somewhat longer than the segment itself 
and is prolonged over the proximal part of the 18th segment. 
The toothed-plate on the 18th segment extends the whole length 
of the joint, that of the 19th segment bears teeth the whole 
length of the segment and is then produced as a spinous process 
beyond the distal extremity. 
The 5¢h pair of legs is as figured. 
The shape of the last thoracic segment and the coarse saw on 
the exopodites of the legs serve to distinguish it from other mem- 
bers of the genus. 
I have much pleasure in dedicating this species to Lt.-Col. 
A. Alcock, who for many years was Surgeon Naturalist and subse- 
quently became the Superintendent of the Indian Museum. 
Genus Labidocera. 
Labidocera euchaeta, Giesbrecht. 
Stage 1, Dimorph. 1, nov. 
Pl. xviii, figs. I—9. 
2 Total length 2°64 mm. 
The head is separate from the Ist thoracic segment and is 
subdivided into two regions, an anterior and a posterior, by a 
deep groove that runs transversely across the dorsum, separating 
the part that carries the two antennae from that which bears the 
mouth-parts. The 4th and 5th thoracic segments are fused, and 
the posterior thoracic border is produced backwards in an angular 
process as in L, wollastont. Anteriorly the head forms a promi- 
nent bulge terminating below in a pair of long retrorse rostral 
spines. There is no rostral lens but a ventral lens is present. 
Although well marked this forward bulge of the forehead is not so 
distinct as in the earlier stage (stage 2). Side hooks are absent. 
The abdomen is composed of two joints only, the 2nd or 
posterior of which is very short. The furcal rami are symmetrical 
and the furcal setae are of practicatly equal length. 
