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



as a well defined, though rather short, acutely pointed rostrum, somewhat compressed in 

 its outer part. 



The caudal segments in the Challenger specimen would appear to be c|uite smooth 

 above, whereas in that obtained by Mr. Lumholtz a distinct, though very small, dentiform 

 process is seen projecting above from the end of the third segment. The epimera are 

 of the usual appearance, rather small in the Challenger specimen, a trifle larger in the 

 other. The last segment is somewhat longer than the preceding, and exhibits at the end. 

 inferiorly, a well-marked unguiform preanal spine. 



The eyes are exceedingly small, more so even than in Thysanopoda ohtusifrons, and of 

 a rounded form, with the cornea occupying about the outer half of the eye. 



The antennular peduncle is rather strong, and not unlike that of Tliysanopoda ohtusi- 

 frons in form, having, as in that species, a densely hispid lobe projecting above from the 

 end of the basal joint. This lobe, however, has in the present species the outer corner 

 drawn out to a strong spiniform jirojection, and, moreover, another but much smaller 

 lobe occurs extending above from the second joint. 



The antenna! scale would appear to have much the same form as that in Tltysanopoda 

 ohtusifrons, though perhaps a trifle more oblong. 



As regards the oral parts and the gills, no detailed examination could be made, for 

 want of sufiicient material. 



The legs present apparently a close resemblance to those in Thysanopoda ohtusifrons, 

 saving, however, that the penultimate pair is relatively somewhat shorter. 



As stated above, the outer part of the tclson was broken oft" in the Challenger 

 specimen. In the other (Mr. Lumholtz's) it is of moderate size, and furnished with about 

 nine pairs of small dorsal denticles, exclusive of the subapical spines, which are somewhat 

 slender and smooth. 



The uropoda, when extended posteriorly, reach a little beyond the tip of the telson, 

 and have the inner j)late but very little shorter than the outer. 



Habitat. — The Challenger specimen was taken at the surface of the sea, in the North 

 Atlantic, May 3, 1876 ; lat. 26° 21' N., long. 33° 37' W. 



The specimen procured by Mr. Lumholtz was likewise obtained with the surface-net, 

 but in the tropical region of the Atlantic, lat. 7° N., long. 23° W. 



The distribution of the species as yet known, would accordingly appear restricted to 

 the Atlantic Ocean. 



Genus. 3. Bentheuphaitsia, n. gen. 



Generic Characters. — Body scarcely compressed. Ej'es imperfectly developed. 

 Flagella of Ijoth pairs of antennae greatly elongate. Antennular peduncle remarkably 

 short and stout. Oral parts very peculiar in structure. Mandibles strongly developed, 



