REPORT ON THE SCHIZOPODA. 113 



Willemoes-Suhm, who simply states in his manuscript notes, that they occurred as a 

 mere rudiment. On dissecting one of the specimens in the collection, I found them, 

 however, developed precisely as the rest, both the exopod and cndopod being well defined, 

 the latter as a distinctly articulate stem, differing merely in haviug the terminal part 

 very small and composed of only two articulations. 



The gills (see figs. 16-24), although on the whole presenting the structure and 

 arrangement characteristic of the family, yet exhibit certain striking peculiarities. They 

 increase successively in size posteriorly, and become, as they do so, more complex in 

 structure, the three hindmost pairs being richly arborescent. In no other form of 

 Euphausiidse does the homology of the gills to the epipod admit of being better 

 demonstrated than in the present animal. For in the anterior pair (see figs. 16 and 19) 

 the epipod-plate retains precisely the original aspect it has in the maxillipeds, whereas 

 the true branchial part is found to be merely an out-growth from the exterior face of this 

 plate, in the form of a curved stem fringed along its posterior edge with a regular series 

 of gill-lobules of the usual structure. In the second pair (fig. 20) the interior extremity 

 of the epipod-plate has become somewhat produced, and from its apex a single minute 

 gill-lobule has taken origin, whereas the outer gill-stem remains unaltered. In the third 

 pair (fig. 21) the inner part of the epipod-plate has taken a still more striking gill-like 

 aspect, several other gill-lobules having made their appearance on its edge ; and in the 

 following pair, this would appear characteristic to a still greater extent. Finall}', in the fifth 

 and sixth paii's (figs. 22, 23), the inner part of the epipod-plate has been so greatly 

 modified as to assume the aspect of the principal part of the gill, furnished, as it is, with 

 several spirally arranged gill-stems, each subdivided into numerous lobules. Yet in aU 

 those pairs, the outer part of the epij)od-plate has remained almost unchanged, forming a 

 simple rounded lobe, of a peculiar, as it were spongy structure, and projecting above the 

 true gills (see fig. 1). The last pair of gills (see figs. 18-24) are very large, and, as usual, 

 exhibit two principal diametrically diverging sections, both of which are divided into 

 numerous secondary branches, partly spiral in arrangement, and all of them furnished at 

 one of their edges with a regular series of gill-lobules. 



The pleopoda (fig. 25) do not exhibit any marked peculiarities of structure. 



The telson (see fig. 3) is relatively less produced than in other Euphausidians, and 

 scarcely longer than the last segment. Moreover, it is somewhat flattened throughout, 

 tapering gradually toward the apex, which is sharply pointed. The subapical spines are 

 rather slender, reaching far beyond the tip of the telson, and perfectly smooth. On the 

 dorsal face of the telson occur in addition two pairs of very small denticles. 



The uropoda (ibid.) scarcely extend beyond the telson, and have both plates compara- 

 tively br(.iad and lamellar. The inner plate, which is the shorter, is lanceolate and 

 fringed all round with plumose setae. The outer plate is oblong in form, and exhibits, 

 contrary to what is the case in other Eupliausiidae, in its outer part a distinct 



(ZOOL. CHALL. EXP. PART XXXVH. — 1885.) Oo 15 



