00 THE VoVAGE OF H.M.S. CHALLENGER. 



Rostrum narrow, linear, short; laterally it is slightly covered by the edges of the 

 rostra] latus. 



Rostral latus with the umbo slightly protuberant, of an irregular quadrangular 



shape. 



Infra-median latus stout, almost as broad as it is high, pentagonal. 



Carinul A itn* of an irregular shape. Umbo at one-third of the height of the valve 

 from the base, slightly protuberant, Superior part of the carinal margin hollowed out, 

 lateral margin long and at a right angle with the basal margin. 



Length of the capitulum, 7£ mm. 



Peduncle cylindrical, almost G mm. long, slightly thicker towards the upper extremity. 

 The scales at considerable distances from one another placed in longitudinal rows. A 

 full-grown specimen shows about seven of these rows, each containing about nine scales. 

 Each scale is straight near its attachment, and has a rounded free edge. 



Mouth. — The anterior part of the labrum forms an overhanging projection; the palpi 

 are small, short, triangular, with a tuft of spines at the extremity. The mandibles have 

 three teeth, the first and the second are separated by a very deep notch ; the inferior 

 angle is broad and strongly pectinated. The maxillce show a not very deep notch 

 behind the three upper spines, two of which are greater ; the portion behind the notch 

 has the edge nearly straight, and is furnished with five or six pairs of not very unequal 

 spines. The outer maxilhe have the so-called olfactory orifices placed at the end of 

 highly protuberant stalks. 



The cirri in this species are relatively short ; the first pair shows unequal rami ; the 

 shortest one has six segments, the longer ramus eio;ht segments. Those of the former are 

 slightly thicker than those of the other ramus. The segments of both rami are very 

 thickly clothed with very long spines ; the shortest ramus, moreover, shows a very thick 

 spine on the outer side of the upper edge of the third and fourth segments, and two of 

 these stronger spines near the upper edge of the fifth segment, and three at the extremity 

 of the last segment. 



The caudal appendages are small, uniarticulate. 



The eggs are relatively large and not very numerous. 



Convplemental males (PI. IX. fig. 6) one on each side/placed in a pouch formed by the 

 membrane which covers the scutum interiorly. Its attachment and form is much like 

 that of Scalpellum stroemii. The little body itself is covered by a very thin chitinous 

 membrane, which is delicately striated. Of the inward parts almost nothing has remained 

 except the testis and the receptaculum seminis. I could trace also — though not very 

 distinctly — the course of the vas deferens, but I failed to distinguish the place where it 

 opens. 



Of this species great numbers were taken : — Cruise of the " Knight Errant." — Station 

 8, August 17, 1880; lat. GO 3' K, long. 5° 51' W.; depth, 540 fathoms; cold area. 



