664 MRS. E. W. SEXTON ON 



(fig. 11) the inner ramus is about three-quai-ters the length of 

 the 1st joint of the outer ramus ; in G. locusta it reaches to the 

 distal end of the 1st joint, and both i^ami are more richly furnished 

 with spines and plumose setse. 



CoROPHiUM LACUSTRE Yanhoffen, 1911. (PI. LXXIY. figs. 13- 



1911. Beitr. z. Kennt. d. Brackwasserfauna im Frischen Hafi". 



The largest male measured 3 "5 mm. ; the largest female 

 5"5 mm. 



Body broad, hardly at all compressed. Side-plate 1 with three 

 very long plumose setas at the anterior angle. 



Fleon-segmenis 4-6 coalesced, strongly resembling C. acutum 

 Chev. 



Head. The rostrum in the male is much produced, apex sub- 

 acute ; not so prominent in the female, apex obtuse. Lateral 

 lobes rounded, produced, but not to the level of the rostrum. 



Uyes large for the genus, irregularly round, pigment black. 



Antenna 1. — The peduncle in the male is clothed with long 

 hairs ; 1st joint nearly as long as the 2nd and 3rd combined ; in 

 the female (PI. LXXIY. fig. 13) the first joint is longer than the 

 2nd and 3rd taken together ; in both, it is produced below a.pically 

 and tipped with one short stout spine ; 3rd joint much shorter 

 than the 2nd. The flagellum is shorter than the peduncle, about 

 9-jointed in the male and 7-jointed in the female ; terminal 

 joint rudimentary, the last three joints each caiTy a cluster of 

 sensory filaments. 



Antenna 2 very stout ; in the male the large 4th joint of the 

 peduncle carries two apical teeth, the outer one much the larger, 

 recurved. The 5th joint and the flagellum are furnished in- 

 feriorly with clusters of very long fine hairs. The flagellum 

 consists of two joints, the small terminal one with two strong 

 spines. In the female (fig. 14) the 3rd joint of the peduncle is 

 produced apically into a small process tipped with a spine ; the 

 4th joint has a similar process midway on the inferior margin, 

 and a long apical tooth with a spine inset at the tip : 5th joint 

 almost as long as the 4th. The flagellum as in the male, but 

 showing one joint-division more ; one spine on the terminal 

 joint. 



Gnathopod 1 (figs. 15 & 16). — 5th joint longer than the 6th, 

 tapering distally ; 6th as wide at the palm as at the base, but 

 with hind margin lightly curved ; front margin with transverse 

 rows of setae ; the palm convex, serrulate, fiinged with six small 

 spines ; the finger curved, acute, inner margin serrulate, with 

 three or four setules inset subapically. 



Gnathopod 2 (fig. 17) much as in C. triaenonyx Stebbing. The 

 2nd joint is expanded, more so in the male than in the female ; 

 6bh joint long, tapering distally. The finger is tridentate ; teeth 

 upturned, the 3rd the largest, with small stiff sette inset between. 



