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



armed along the edge with a rather large number of strong spines, unequal in size. 

 The palp, unlike that of other Euphausiidse, is distinctly triarticulate, though very- 

 small, the middle joint being the largest, and furnished along the inner edge with a row 

 of strong bristles, whereas the basal and terminal joints are quite unarmed. The 

 exognath, finally, constitutes an oval plate, without any bristles, and of a peculiar almost 

 spongy structure. Moreover, it is specially distinguished by the posterior part being 

 drawn out into a narrow, finely ciliate, lobe. 



The second pair of maxillas (fig. 13) exhibit a perhaps still more anomalous aspect, 

 owing to the prodigious development of the palp. The latter, constituting, as it does, in 

 all other known Euphausiidse, only a single lamellar joint, occurs here as a large trunk, 

 fully equal in length to the remaining part of the maxilla, and composed of three well- 

 defined lamellar expanded articulations, giving to the maxilla, as it were, a pediforni 

 appearance. Of the joints, the first is by far the largest and very broad, oval in form, 

 and fringed along the inner edge with numerous long curving plumose setge. The two 

 outer joints ra])idly diminish in size, and are likewise provided with strong plumose setse 

 along the inner edge, as also a few much shorter ones at the outer. The remaining part 

 of the maxilla exhibits, on the whole, a normal appearance, having interiorly four densely 

 setose masticatorv lobes, and extcriorlv a small lamellar exo2;nath edged Avith short 

 ciliate bristles. 



The maxillipeds (fig. 14) exhiliit the usual pediform structure, having, however, the 

 proximal part remarkably roljust, with the joints much appressed, whereas the distal part, 

 consisting of the outer three joints, would seem to be somewhat slender and very movably 

 jointed to the former. The meral joint, by f;ir the largest, slightly exceeds in length the 

 distal part. All the joints are provided along the inner edge with a number of slender 

 scattered bristles. The masticatory lobe, issuing internally from the coxal joint, is found 

 on closer examination (see fig. 15) to consist of two superposed lappets, both edged with 

 strong curving setae. The exopodite is rather powerfully developed, reaching beyond 

 the middle of the meral joint. The epipodite, finally, constitutes a small membranous 

 plate, projecting both anteriorly and posteriorly as a rounded lobe. 



All the legs, save the last pair, had been broken off in the sjiecimens I examined, only 

 their basal parts along with the gills and exopods being left. In the specimen, however, 

 examined by the late Dr. v. Willemoes-Suhm, they had suffered no mutilation and were 

 fully represented in the figure drawn by that naturalist, of which the annexed cut is an 

 accurate copy. As seen from the figure, they are rather elongate, but relatively coarser 

 in structure, than in other Euphausiidaj, the joints being much appressed and densely 

 setose. 



The last pair of legs (fig. 18) are much smaller than the rest, and in the specimens 

 examined were almost entirely hidden between the gills, so as readily to escape attention. 

 Hence, too, they came to be quite overlooked by myself as also by the late Dr. v. 



