REPORT ON THE SCIIIZOPODA. 100 



preceding, preaual spine obsolete. Eyes very short. Antcnnular peduncle without 

 distinct dorsal lappets, but exhibiting an unusually strong seta that issues from inner 

 corner of last joint. Antennal scale oval in form, with rounded apex and outer corner 

 jutting out as a well-defined tooth. Telson with six pairs of dorsal denticles, apex but 

 slightly produced, subapical spines smooth. Inner plate of uropoda shorter than outer. 

 Length 55 mm. 



Remarks. — There cannot, I think, be any doubt whatever as to this form also being a 

 true Thysanopoda, though the oral parts and gills could not in the single specimen taken 

 be submitted to a close examination. The species may be readily distinguished from 

 either of the two preceding ones by its strongly compressed body, elevated dorsal crest, 

 and peculiar rostrum. 



Description. — Only a single specimen of this species, an adult male, was secured. It 

 has a length of as much as 55 mm., and accordingly ranks among the largest forms of 

 the Euphausiidfe. 



The body (see PI. XVIII. fig. 15) is rather stout, but very much compressed 

 throughout. 



The carapace lacks, as in Thysanopoda ohtusifrons, every trace of lateral denticles, 

 the inferior margins being quite smooth and evenly incurved along the middle. The 

 anterior part has a well-marked and somewhat elevated crest in the middle, and juts out 

 as a distinctly developed rostrum, reaching almost to the end of the basal joint of the 

 antennulfB. The form of the rostrum is also in this species somewhat ditferent from 

 that usually met with in the Euphausiidse, being somewhat cultrate, with a sharp carina 

 both at the upper and the lower side, the former constituting a continuation of the 

 dorsal crest of the carapace. Its apex is drawn out to a sharp somewhat deflexed point, 

 and a little behind the latter a very small denticle occurs on the upper edge of the 

 rostrum. 



The caudal segments are very powerfully developed, with rather large epimera of a 

 slightly irregular form, the three middle ones being, as in Tliysanopoda ohtusifrons, 

 sinuate along the inferior edge. The three anterior segments are quite smooth above, 

 whereas the two succeeding ones exhibit a small spiniform projection in the middle of 

 the posterior margin. The last segment scarcely exceeds in length the preceding, and 

 does not exhibit any trace of a preanal spine. 



The eyes (see figs. 15, 16) are very short, almost globular in form, and [)roject but 

 little, if at all, beyond the sides. 



The antennular peduncle (see fig. 16) is rather strong, with the anterior border of 

 the basal joint somewhat thickened and densely setose, though not constituting a true 

 lobe, and the outer corner is produced as a spiniform projection. The second joint 

 projects above at the end as a small triangular lappet, overlapping the base of the 

 terminal joint. The latter exhibits at the inner edge, near the tip, a remarkably strong 



(ZOOL. CHALL. EXP. — PART XXXVII. — 1885.) Oo 14 



