174 



geniculated setse; 1st joint of inner ramus very long and narrow, being more 

 than 3 times as long as the other 2 combined, last joint only slightly longer 

 than the 2nd, and carrying at the tip a slender claw and a somewhat longer geni- 

 culated seta. Natatory legs with the rami rather narrow, the inner one consider- 

 ably shorter than the outer, setse exhibiting a similar reduction in number to 

 that found in A. debilis. Last pair of legs of moderate size, distal joint oval in 

 form and somewhat tapered towards the end, with 5 rather short marginal setse ; 

 inner expansion of proximal joint comparatively short, triangular in form, and 

 extending scarcely beyond the middle of the distal joint, marginal setse 5 in 

 number. Ovisacs small and only slightly divergent, each containing, as a rule, 

 only 3 ova arranged in a single row. 



Colour not yet ascertained. 



Length of adult female 0.36 mm. 



Remarks. This is one of the smallest of the species of the present genus, 

 and exhibits, in the structural details, some resemblance to A. debilis (Glaus). It 

 is however easily distinguished from that species by its much shorter and stouter 

 body; and on a closer comparison, some well-marked differences are also found 

 in the structure of the several appendages. 



Occurrence. Some few specimens of this dwarfed form, all of the female 

 sex, were found in the same sample in which A. phyllopus occurred. 



114. Amphiascus exiguus, G. 0. Sars, n. sp. 



(PI. CXIV, fig. 2). 





Specific Characters. Female. Body very narrow, sublinear in form, 

 scarcely tapering at all behind. Cephalic segment of moderate size and narrowly 

 rounded in front; rostrum rather produced, lanceolate. Urosome almost as long 

 as the anterior division, segments coarsely spinulose at the hind edge ventrally 

 and laterally. Caudal rami comparatively small, about as long as they are broad, 

 apical setse of normal appearance. Eye not visible in the living animal. Anterior 

 antennse comparatively short, 8-articulate, 2nd joint much the largest, fully as 

 long as the 2 succeeding ones combined, terminal part not nearly half as long 

 as the proximal part, and having the 3 first joints very small, and combined 

 scarcely longer than the last joint. Posterior antennse about as in the preceding 

 species. 1st pair of legs with the outer ramus considerably exceeding half the 

 length of the inner, middle joint without any seta inside, last joint of about the same 

 size, and armed with 2 spines and 2 geniculated setse; inner ramus with the 1st 



