1886.] DURING THE VOYAGE OF H.M.S. 'CHALLENGER.' 103 



single elongated claw ; the autennule has a four-jointed peduncle 

 and a long multiarticulate flagellum ; the uropoda are defective but 

 evidently are of considerable size, judging from the socket of articu- 

 lation. The whole body is covered with short slender spines of 

 varying size, but nowhere very long. 



I. ACANTHOMUNNA PROTEUS, n. Sp. 



This species, the only one referable to the genus, is represented 

 by two individuals, both males, dredged off New Zealand in 700 and 

 1000 fathoms respectively. Tlie larger specimen measures 7 millim. 

 in length. The general shape of the body is as in Munna, but differs 

 in being covered with innumerable spines, many of which are 

 branched ; the spines are nowhere of very great length. The head 

 is furnished with a pair of eyes situated laterally ; these are elevated 

 upon short stalks ; the abdominal shield is preceded by a short Iree 

 abdominal segment ; it is extremely convex anteriorly, and the 

 point of articulation of the uropoda is upon the dorsal surface, 

 though near to the lateral margin ; behind the articulation of their 

 appendages, the abdominal shield is flattened and terminates in 

 a truncated, slightly concave extremity. The antennules have a 

 four-jointed peduncle, the third joint being the longest, and a 

 multiarticulate flagellum longer than the peduncle. The mandibles 

 have a palp. The first pair of thoracic appendages are shorter than 

 the rest and subcheliform ; the remaining thoracic appendages are 

 very long, owing to the elongation of the fourth and fifth joints ; they 

 terminate in a single claw ; these appendages are covered with slender 

 unbranched spines, which arise from tubercles. The uropoda are 

 defective, but appear to have been larger than those of Mmma, &c., 

 and possibly more fully developed. 



Station 168; 1100 fathoms. Station 1G9; 700 fathoms. 



Fam. AsELLiD^. 

 Genus Stenetrium, Haswell. 



I. Stenetrium haswellt, n. sp. 



A single species of this genus, the only known deep-water species, 

 was dredged off' the coast of S. America in 600 fathoms. The 

 specimen is a male, and measures 16 millim. in length. 



The diameter of the body is everywhere much the same except the 

 head and the terminal region of the abdominal shield. The head is 

 prolonged into a short rostrum ; eyes are presentof narrow linear shape, 

 and set obliquely. The thoracic segments are subequal in length as 

 well as breadth, and the dorsal surface is quite smooth ; the margins 

 of the first thoracic segment are prolonged into a triangular spiny 

 process ; in the second segment the margin is furnished with a 

 smaller spine-like process ; in the two following segments there is 

 in addition a smaller posterior spine ; in the fifth segment the 

 antero-lateral spine is much wider, occupying nearly the whole of 

 the lateral margin ; in the two remaining segments, the lateral 



