AND ON THE NORTH EAST COAST OF ENGLAND, 59 



pairs having the outer branch three-jointed, the inner two- 

 jointed ; antennules nine-jointed. 



Paratachidius inermis, sp. nov. (PI. II., figs. 12-17; 



pi. IV., figs. 13-14). 



Like Tachidius in general appearance ; the penultimate and 

 antepenultimate segments of the abdomen fringed on their 

 distal margins with fine setae (PI. II., fig. 16), caudal segments 

 twisted, subsigmoid, somewhat shorter than the last ab- 

 dominal segment, bearing two principal setse at the apex, the 

 outermost of which is about half as long as the inner one, and 

 is acutely bent at the base (figs. 16, 17), the lateral margins 

 also bear a few small setae. Antennules nine-jointed (fig. 12), 

 slender; the joints nearly equal in length (except the last, 

 which is short), but gradually narrowing to the extremity ; all 

 the joints bearing fine, but not very long, setae. Antennae 

 comparatively large and stout (fig. 13), inner branch consist- 

 ing of a single joint ; posterior footjaws small, the hand ovate 

 and simply unguiculate (fig. 14). Outer branch of the first 

 pair of swimming feet rather shorter than the inner branch 

 (fig. 15), each joint bearing a large apical spine on the outer 

 margin, outer margins of both branches ciliated : outer 

 branches of the second, third, and fourth pairs (PI. IV., 

 fig. 13) longer, the last joint being about twice as long as the 

 preceding ones ; inner branch short, two-jointed, the first joint 

 almost rudimentary. The joints of the fifth pair of feet are 

 narrow and elongated (fig. 14), and bear several unequally 

 long setse. Length about "5 mm. 



Only one example of this species was found in a gathering 

 taken among algae in tide-pools, Filey Brigg, Yorkshire, 

 August, 1897. 



Genus PSEUDOTHALESTRIS, G. S. Brady. 



Pseudothalestris monensis, sp. nov. (PI. III., figs. 11-16). 



Cephalothorax oi the fetJiale, seen laterally (fig. 11), stout, 

 with a strongly conyex dorsal curve, abdomen muchmore 



