REPORT ON THE SOIIIZOPODA. 43 



phausia zoea in its general form, but distinguished botli from that and all the other 

 species by the absolute want of the upper lateral keel, and by the distinctly impressed 

 cardio-branchial sulcus. 



Description. — ^Of this species, too, a solitary specimen only was obtained, a female, 

 with distinct though not j^et fully developed incubatory lamellse. Length of the 

 specimen only 56 mm. 



The form of the body (see figs. 1, 2) is more slender than in any of the other species, 

 excepting perhaps Gnathophausia gracilis, Suhm. 



As in the preceding species, the carapace does not cover completely the last segment 

 of the trunk, part of which may be seen exposed behind its posterior margin. It juts 

 out posteriorly as a comparatively strong dorsal spine, which, however, does not project 

 beyond the second caudal segment. Of the lateral keels the lower only is distinctly 

 developed, and this curves obliquely upward in its posterior part, terminating at some 

 distance beneath the base of the dorsal spine. The upper lateral keel, on the other hand, 

 distinct in all the other species of the genus, would seem in this one to be wholly 

 wanting. Only when viewed from the dorsal aspect (fig. 2) can two faint lines be 

 diseerned, close to the dorsal keel, which, perhaps, may be regarded as corresponding to 

 these keels, but, if so, they have a most anomalous position. The rostrum is rather 

 elongate, attaining the length of the whole carapace, and is coarsely denticulate, the 

 denticles being continued along the upper crest to the base itself, becoming here very 

 small and crowded together. The supra-orbital spines are distinctly developed and 

 somewhat upturned. On the other hand, the antennal spines are exceedingly small; 

 and of the branchiostegal spines no trace whatever can be discerned, the lateral 

 expansions of the carapace behind the antennal spines being evenly rounded, as in 

 Gnathophausia ivillemoesii. 



The caudal segments are rather slender, and, as in Gnathophausia affinis, without 

 any keel or dorsal projections. The epimera are very small, the posterior lappet scarcely 

 projecting beyond the ventral face. The last segment is conspicuously longer than the 

 preceding, and its two sections very distinctly marked off. 



The eyes, as in the two preceding species, are quite short, and clavate in form. 



The antennal scale (fig. 3) is more than double the length of the antennular j)eduncle, 

 and of a form rather similar to that in Gnathophausia affinis, with this difference, however, 

 that the terminal lobe is much less produced, the spine of the outer corner projecting 

 considerably beyond it. This spine, too, contrary to what is the case in the following 

 species, is quite smooth. 



The telson (fig. 4) exhibits the usual linguiform shape, the lateral margins being 

 rather strongly curved in their distal part, and densely spinulose. The apical spines are 

 somewhat short and thick, armed at the outer edge with a small tooth, and separated in 

 the middle by a distinctly angular cleft, fringed with small denticles (see fig. .5). 



