314 DE, THOMAS SCOTT ON THE 



Pseudothalestris assimilis, G. 0. Sars, var. antarctica, nov. var. (PI. IX. figs. 5-9.) 



A single specimen — a male — closely resembling, if it be not identical with, the 

 male of the species referred to, described by G. 0. Sars in his Crustacea of Norway, 

 vol. V. p. 141, was obtained in the same gathering with P. intermedia, collected in 

 Scotia Bay, South Orkneys, Station 325, 60° 43' 42" S., 44° 38' 33" W. But though 

 agreeing with some of the more important characters of that species, it differed in one 

 or two minor points. In the first pair of thoracic legs the seta on the inner margin of 

 the first of the inner ramus was situated nearer the proximal end of the joint. 



The inner produced portion of the basal joint of the fifth pair is narrower, and the 

 second joint is broader, and further, this joint is only provided with five instead of 

 six setae (see fig. 8). On account of these differences, I am inclined to regard this as a 

 variety of the species it otherwise so closely resembles. 



Fam. DiosACCiD^. 

 Genus Diosaccus, Boeck, 1872. 

 Diosaccus tenuicornis (Glaus). 



1863, Dactylojiiis teuiiicornis, Clans, Die freileh. Copep., p. 127, pi. xvi. figs. 17-23. 



1880, Diosaccus tenuicornis, Brady, Monoijr. Brit. CoiKp., vol. ii. p. 68, pi. lix. figs. 12-16, pi. Ix. 



figs. 14-18. 

 1906, Diosaci'us tenuicornis, G. 0. Sars, Crust, of Norivaij, vol. v. p. 146, pi. Ixxxix. and xc. 



A single specimen — a male — was obtained in a tow-net gathering from Station 85, 

 collected on 22nd December 1902, 23° 8' S., 39° 40' W. 



Genus Amphiascus, G. 0. Sars, 190.5. 

 Amphiascus fucicolus, new species. (PI. IX. figs. 23-28.) 



Female. — Somewhat like Amphiascus similis (Glaus) in general appearance ; 

 rostrum prominent ; abdomen strongly flexed. Length about 0"8 mm. 



Antennules eight-jointed ; first and second joints robust and subequal ; the next 

 two shorter and not so much dilated ; the fifth and seventh joints are smaller than any 

 of the others ; the sixth is nearly as long as the fourth, while the last, which is narrow, 

 is about equal in length to the third (fig. 23). 



In the first pair of thoracic legs, the outer ramus is considerably shorter than the 

 inner one, and the middle joint is about twice the length of the first (fig. 26). In the 

 fourth pair, the outer ramus is rather longer than the inner one (fig. 27) 



The fifth pair of legs are of moderate size and broadly foliaceous ; the interior 

 of the basal joint, which is only slightly produced, is provided with two short and 

 three tolerably long slender hairs on the distal margin ; the second joint has a sub- 

 quadriform outline, the length being only a little greater than the width ; its distal end 

 is obliquely truncated and furnished with five setas of unequal lengths — one near the 



(hoy. soc. edin. trans., vol, slviii., 5G0.) 



