Entomostraca from the Scottish Seas. 128 



(G. 0. Sars) ; Metridia princeps, Giesbrecht ; and various 

 others to be described later. 



Halocypridae. 



Genus Euconchcecia, G. W. Mttller, 1890. 



Euconchoecia d'ai'cy-thompsoni, sp. n. 

 (PI. III. fig. 19 ; PI. IV. figs. 1-12.) 



Shell, seen from the side, oblong; length scarcely equal to 

 twice the width. Dorsal margin nearly straight, each valve 

 terminating posteriorly in a small pointed process, while in 

 front the rostral projection, which is distinctly bifid, is 

 bounded beneath by a deep sinus, as shown in the drawing 

 (PI. IV. figs. 1&2); ventral margin nearly parallel with the 

 dorsal and slightly but evenly rounded; posterior end sub- 

 quadrangular ; anterior end boldly curved ; shell-gland near 

 the postero-dorsal angle, as shown in the drawing (PI. IV. 

 fig. 2). 



Length of the shell represented by the drawing about 

 4*7 mm. 



The antennules are each provided at the apex with a dense 

 fascicle of very slender bristles and with three (or four) setae; 

 two of these seta? are long and slender, but of unequal length, 

 one being much more elongated than the other (PL IV. fig. 5). 



Antennae similar to those in Euconchoecia chierchice, G. W. 

 Miiller; the secondary branch on the right side is armed 

 with a strong hook (PI. IV. fig. 6), that on the left side is 

 also provided with a hook, but it is much smaller than the 

 other. 



.Mandibular foot nearly as in Conchaecia elegans, the masti- 

 catory part armed with several small teeth (PI. IV. fig. 7). 



First foot slender and moderately elongated, end joint very 

 small, with one long and moderately stout seta and two other 

 smaller ones (PI. IV. fig. 9). Second foot considerably 

 shorter than the first (PI. IV. fig. 10). 



Caudal lamina somewhat similar to that of E. chierchice, 

 Miiller, except that it is armed with eight spines ; the prin- 

 cipal spine exhibits the same number of articulations as that 

 of the caudal lamina in the species named. Oopulatory 

 organ rather narrow and elongated (PI. IV. figs. 11 & 12). 



The female does not differ greatly from the male, except 

 that the rostral hood-like projection at the anterior end of the 

 shell is not bifid as in the male (PI. IV. fig. 4) and that the 

 accessory branch of the antenna has no hook-like appendage 



