CHALARASPIS ALATA. 183 



distinctly keeled. The postero-lateral part of the carapace at each side is some- 

 what produced backwards and rounded as in Eucopia. 



The eyes (fig. lb, o.) are small, a little compressed, seen from above (fig. la) 

 obliciue-ovate, light reddish. — The antennular peduncles short and extremely 

 thick; second joint with an oblong, slender, moderately short process on the 

 outer side; third joint with the front margin projecting in an oblong, very acute 

 process above the insertion of the upper flagellum and a somewhat similar 

 process more downwards on the inner side of the joint; the upper flagellum 

 thin, with numerous joints and about as long as tlie peduncle; lower flagellum 

 very strong. — Last joint of the antennal peduncle with a small process on the 

 outer side just below the insertion of the squama; the scjuama itself is a thin 

 plate reaching somewhat beyond the end of the antennular pediuicle, it is some- 

 what more than twice as long as broad (fig. Ic) with the inner margin very 

 convex and setose, the outer margin a little bent angularly near or a little bej'ond 

 the middle and its proximal part glabrous, the distal part serrate with 9-12 

 acute saw-teeth somewhat different in size. 



The five anterior abdominal segments somewhat thick, dorsally flatly 

 convex, and some among them even with a small, a little excavated dorsal 

 area; lateral plates of the anterior segments rounded, on fifth, and sometimes 

 on fourth, segment the postero-lateral angle is jiroduced in a tiny or small, 

 acute tooth. Sixth segment about as long as the fifth, with two pairs of obliquely 

 transverse, somewhat short and shallow furrows; the two pairs of lateral teeth 

 very acute. The uropods (fig. 11) with the endnpods slightly overreaching 

 the telson and a little longer than the exopod, wliicli has the end truncate and 

 three or four faint serrations along the outer margin. Telson (fig. 11) very 

 oblong-triangular, scarcely three times as long as broad, above with a pair 

 of high, longitudinal, very feebly serrate keels a little from the lateral margins, 

 and the area between these keels excavated longitudinally; the distal half of 

 each lateral margin with 5 or (i spines; the end of the telson truncate, but hairs 

 or spines wanting — perhaps lost? — in the specimens. 



Length of the largest specimen, a probably adult male, 35 mm. 



Remarks. — I do not entertain the slightest doubt that the species descri])ed 

 here is C. alaia. And I think it very important that it has been possible to fill 

 the gap in our knowledge of the only hitherto imperfectly studied genus of the 

 small but highly interesting sul^order Lophogastrida. 



Distribution. — The "Challenger" .specimen was taken in the South Pacific: 

 " lat. 50° 1' S., long. 123° 4' E.; depth, 1800 fathoms." It is certainly a bathy- 

 pelagic form. 



