as in the typical species. 1st pair of legs with the outer ramus of moderat 

 size, seta attached inside the middle joint of unusual length, last joint almost as 

 long as the other 2 combined, and carrying at the tip 2 spines and 2 geniculated 

 seta?; inner ramus only slightly exceeding in length the outer, and less distinctly 

 prehensile than in the typical species, 1st joint much shorter than the other 2 

 combined, last joint somewhat longer than the middle one, and, as in C. stapliy- 

 linus, carrying on the tip a slender spine, a still more slender seta, and a very 

 small hair-like bristle. Natatory legs comparatively less slender than in that 

 species, with the inner ramus shorter in proportion to the outer, though of the 

 structure characteristic of the genus. Last pair of legs resembling in shape those 

 of C. staphylinus, inner expansion of proximal joint, however, comparatively larger, 

 extending beyond the middle of the distal joint and provided with 6 marginal 

 spines, the 2 outermost ones much shorter than the others. Ovisac oblong oval 

 in form, extending to the end of the urosome. 



Male with the inner ramus of 2nd pair of legs conical in form, and hav- 

 ing the outer 2 joints wholly confluent, sub-apical spine wanting; that of 3rd pair 

 transformed in a similar manner to that in the male of C. staphylinus, the 

 mucroniform process of 2nd joint, however, still longer, terminating in a very 

 slender point; inner ramus of 4th pair not differing from that in the female, ex- 

 cept in the smaller number of setae, that of the 1st joint and the proximal one of 

 the last joint being absent. Last pair of legs with the distal joint comparatively 

 smaller than in the male of C. staphylinus, differing also somewhat in shape. 



Colour whitish. 



Length of adult female 0.56 mm. 



Remarks. This form was first recorded, though rather imperfectly, by 

 Glaus under the above name, and was subsequently described by Dr. Rehberg as 

 a new species under the name of C. lucidulus. It is easily distinguished from 

 the typical species by its much smaller size and shorter anterior antenna?. An- 

 other character by which this form differs from all other known species, and to 

 which also Glaus has called attention, is the peculiar structure of the spinules 

 fringing the anal opercle, all of them being bifid at the tip. 



Occurrence. Only some few specimens of this form have hitherto come 

 under my notice. They were taken in the neighbourhood of Christiania, from 

 shallow ditch in company with Attheyella pygmcea G. 0. Sars. 



Distribution. Sweden (Lilljeborg), Germany (Glaus). Holland (v. Breemen), 

 British Isles (Scott). 



