212 THE VOYAGE OF H.M.S. CHALLENGER. 



slides in shallow cells, whereby the body has been partially crushed and deformed. The 

 anatomical details have, however, been satisfactorily made out from the dissection of one 

 of the specimens. 



Description. — The length of the adult female is about 14 mm., that of the male 

 nearly the same. 



The form of the body (see PI. XXXVII. fig. 1) would appear to be rather short and 

 robust, with the tail relatively less elongate than usual, in proportion to the anterior 

 division. 



The carapace does not nearly cover the whole of the trunk, the two posterior 

 segments of which are well nigh entirely exposed. It is evenly emarginate posteriorly, 

 and exhibits in its anterior part a distinct, though not particularly deep, cervical 

 impression. The frontal margin juts out in the middle as a narrow acuminate lappet, 

 projecting between the bases of the eyes and reaching to about the middle of the basal 

 joiut of the antennulse. 



The tail does not exceed in length the anterior division of the body, and has the 

 segments rather thick in proportion to their length. The last segment only slightly 

 exceeds the preceding in length. 



The eyes — separated at the base by a distinct interval — are of moderate size, and 

 extend to each side so as to project considerably laterally. They are pyriform in shape, 

 about as long as broad, wdth the cornea rather expanded, and exhibiting in the middle a 

 similar constriction to that seen in the species of the Euphausiidan genera, Thysanoessa, 

 Nematoscelis, and Sti/locheiron. 



The antennular peduncle (fig. 2) presents quite a normal appearance, being somewhat 

 dilated towards the apex, with the last joint about as long as the basal, and having three 

 strong ciliated setae springing from the inner edge. In the male, a hairy lobe projects, 

 as usual, from the end of the peduncle beneath the insertion of the flagella. The latter 

 were both broken off near their base in the specimens examined. 



The antennal scale (fig. 3) only slightly exceeds in length the antennular peduncle, 

 and exhibits an oblong-linear form, about four times as long as broad. It is somewhat 

 curved outwards, and has the exterior edge naked and slightly concave, jutting out at the 

 end as a very strong dentiform projection. The apex is obliquely truncate, having the 

 inner corner projecting and fringed, together with the whole inner edge, with about 

 seventeen unusually strong and densely cdiate setae. The proximal part of the flagellum 

 does not attain the length of the scales, and has the middle joint longest, with three 

 plumose setae at the end interiorly. 



The anterior lip (fig. 4) exhibits the usual somewhat galeate form, with an obtusely 

 rounded prominence anteriorly. 



The posterior lip (fig. 5) has the terminal lobes obliquely rounded and densely ciliatc, 

 with a slight angle exteriorlv. 



