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



sulcus, to the bottom of which a series of slender ciliated setae seems to have been 

 affixed, the bases of most of them being still present. From the tip of the lamella a 

 fragment of what may have been either a strong spine or a very elongate seta projects, 

 and external to this another similar spine or seta may have been affixed. The whole 

 lamella exhibits a delicate parenchymatous structure similar to that of the branchial legs. 



As the younger specimen is rather pellucid, some of the internal parts can also be 

 faintly made out through the integuments. Thus, in a lateral view (fig. 1), a dark string 

 is seen running from the cephalic part through the whole trunk and part of the pleon, at 

 some distance from the dorsal surface. On examining the animal from the dorsal side, 

 this string is found to be composed of two symmetrical narrow tubes filled with an 

 opaque granular mass, and having between them another tube somewhat wider and more 

 transparent. It therefore seems evident that the string referred to must represent the 

 intestine, together with two elongate caeca accompanying it in the greater part of its length. 

 But, besides, the anterior part of the body contains another internal organ of far greater 

 dimensions, constituting a large opaque mass slightly tapering posteriorly and extending 

 through the greater part of the trunk at a short distance from the ventral surface. The 

 significance of this body I am unable to state with certainty. It cannot represent the 

 generative organs, since it apparently forms an unpaired mass, and, moreover, its situa- 

 tion would seem to forbid such an assumption. I am more inclined to regard it either 

 as a kind of liver, or perhaps more properly an accumulation of fatty deposits, answering 

 to the adipose body which in Nebalia envelops the whole intestine together with its 

 caeca. The ventral ganglionic cord — only with great difficulty examined in the two other 

 genera — is here immediately visible when the animal is examined from the lower side 

 (fig. 2), lying, as it does, immediately inside the ventral cuticle and not being concealed by 

 the branchial legs. The ganglia of the trunk, placed in the two other genera so closely 

 together as almost to be coalescent, are in this animal wide apart and connected by very 

 long commissures, in close proximity to each other. The ganglia of the pleon, of which 

 at least the anterior is very distinctly seen, are considerably larger than those of the 

 trunk, and furnish several nerve-trunks to each side, from which numerous fine nerves 

 arise, partly innervating the musculature of the pleon and partly entering the pleopoda. 



Habitat. — The first specimen obtained, which, as above stated, was only represented 

 by the carapace and a fragment of the front part of the body, was taken with the dredge 

 in the Southern Ocean between Prince Edward Island and the Crozets. 



Station 146, December 29, 1873; lat. 46° 46' S., long. 45° 31' K; depth, 1375 

 fathoms; bottom, Globigerina ooze ; bottom temperature, 35°'6. 



The other more complete specimen came up in the trawl from a very considerable 

 depth in the South Pacific, about midway between New Zealand and Chili. 



Station 289, October 23, 1875; lat. 39° 41' S., long. 131° 23' W.; depth, 2550 

 fathoms; bottom, red clay; bottom temperature, 34° - 3. 



