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



that the specimen under treatment is a male, while that representing the preceding 

 species is a female. 



The integuments are throughout very thin, and in the spirit specimen semi- 

 diaphaneous, so as to admit of the muscular system being distinctly traceable through 

 the skin. 



Here, too, the carapace covers the whole of the anterior division of the body, but is 

 far from being so inflated as in Gnathophausia ingens, its breadth scarcely exceeding 

 its height. The lateral wings are com2Daratively more produced, and terminate in a 

 perfectly straight, mucroniform spine, reaching as far as the end of the second caudal 

 segment. The keels of the carapace, as also the dorsal area, exhibit precisely the same 

 appearance as in the preceding species. On the other hand, the rostrum would seem to 

 have been much more produced, though I cannot myself state its length with exactness, 

 the point having been broken off in the specimen. To judge, however, from the form of 

 its basal part still remaining, it may certainly be inferred to have been at least much 

 more elongate than in Gnathophausia ingens, and in the figures given by the late 

 Dr. V. Willemoes-Suhm, which were drawn from the recently taken and uninjured specimen, 

 it is in reality represented as being more than half as long as the carapace, and also distinctly 

 denticulate throughout.^ There is, contrary to what is the case in the preceding species, a 

 distinct, though rather small, supra-orbital spine on either side of the base of the rostrum. 

 Moreover, both the antennal and the brauchiostegal spines are distinctly marked. 



The caudal segments do not exhibit the peculiar wrinlded sculpture distinguishing 

 this part in Gnathophausia ingens, only a slight transverse impression being observable at 

 each extremity. On the epimera, too, the anterior lappet is very short, and rounded at 

 the apex, not pointed as in that species. Here, also, the epimeral projections of the last 

 segment are confluent on the ventral face, forming together a cordiform concave plate 

 (see fig. 5), but this is much shorter than in Gnathophausia ingens, and its apical 

 indentation broader. 



The eyes (fig. 3), as in Gnathophausia ingens, are very narrow, but the cornea is 

 much smaller and scarcely expanded at all ; moreover, the ocular papilla is situated closer 

 to the base of the pedicle. 



The antennular peduncle (see fig-s. 1, 2) is greatly thickened, with the second 

 joint exceedingly short, and almost discoid. The outer flagellum is indeed enormously 

 developed, even exceeding in length the whole body, being also very strong and distinctly 

 riband-shaped. The inner flagellum is much more slender, and about the same length as 

 the carapace, exclusive of the rostrum. 



The antennal scale (fig. 4) considerably exceeds in size that of the preceding species, 

 and also exhibits a rather different form, tapering somewhat toward the apex, the inner 



' In PI. in. figs. 1 and 2 given in the present Report, the missing part of the rostrum has been added after the 

 drawings of Dr. v. AVillemoes-Suhm. 



