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



species of the geuus, except, perhaps, that the inner fiagellum is comparatively smaller, 

 not nearly reaching the length of the antennal flagellnni. 



The antennal .scale (fig. 8) is about twice as long a.s the antennular peduncle and 

 rather nai-row, almost three times as long as broad, but in other respect.s exhibiting a 

 structure similar to that observed in the species belonging to the second section of the genus, 

 the terminal part being marked uti' from the remaining portion of tlie scale by a distinct 

 oblique .suture, and jutting out into a .short linguiform lobe. The inner edge of the scale 

 is very slightly arched, and, like the terminal lobe, fringed by a row of comparatively 

 strong bristles. The outer edge, too, is almost straight, and in its distal half slightly 

 serrate, projecting anteriorly into a naked spine of moderate length. 



With regard to the oral parts, they cannot of course be accurately examined in the 

 solitary specimen obtained, Ijut would seem on the whole to agree with those in Gnatho- 

 phattsia longispina, as descril)ed al)0ve; with this diflerence, however, that the maxillipeds. 

 as in the three species belonging to the first section, have distinctly developed exopodites. 



The legs and caudal limbs do not exhibit any essential difi'erence from the same parts 

 in the other species of the genus. 



The telson (see fig. 9) exhibits the usual linguiform shape, and its length about equals 

 that of the two preceding segments taken together. Its lateral edges are evenly curved in 

 their distal part, and densely spinulose. The apical projection exhibits a form somewhat 

 dijferent from that in the other species (see fig. 10), being drawn out into four acute 

 terminal lappets, or spines, the two outer ones being the largest and smooth, whereas the 

 two inner ones are denticulate along the inner edge, and separated by an angular cleft. 

 Moreover, a short denticle is observed on either side at the outer edge of the 

 projection. 



The uropoda {ibid.) do not quite reach the tip of the telson, and they exhibit the 

 usual structure, the outer plate being the larger, and having the terminal part marked 

 off as a distinct joint, jutting out in the form of a rather large linguiform lobe, densely 

 fringed with bristles. The outer edge of this plate is considerably less arched than in 

 the other spe(;ies, and terminates in a very small denticle. 



Habitat. — The specimen described above, together with Gnathophausia affinis, was 

 taken in the tropical part of the Atlantic Ocean between Africa and Brazil. 



Station 107, August 26, 1873 ; lat. 1° 22' N., long. 26° 36' W. ; depth, 1500 fathoms : 

 Globigerina ooze ; bottom temperature, 37°'9. 



Genus 4. Chalarnspis, Willemoes-Suhm (ex parte). 



Generic Characters. — Carapace thin, membranous, of enormous size, covering, in 

 addition to the trunk, the anterior part of the tail, and projecting forwards as a broad 

 troutal plate. Caudal segments with rounded epimera. Eves small. Antennular 



