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



The first pair of pereiopoda is long, slender and simple. The second terminates in an 

 imperfect chela, the pollex being about half the length of the dactylos, but this inequality 

 may be due to the imperfectly developed character of the specimen. The third and 

 fourth pairs are slender, simple, and longer than the preceding, and like them carry a 

 basisal appendage of considerable length. The fifth pair is shorter than the preceding 

 and does not carry an appendage, nor is the basisal joint quite as important as in the 

 four preceding pairs, which are remarkable for their length and robust appearance. 



The pleopoda are biramose. The first pair has the branches unequal, the inner being 

 small and rudimentary. The succeeding pairs have the branches subequal, the inner 

 carrying a single stylamblys. The sixth pair has the rami subequal, and about the same 

 length as the telson ; the outer plate is armed with a feeble tooth at the outer distal 

 angle, and the inner and outer margins as well as the rounded extremity are fringed 

 with slender ciliated hairs. 



The hairs everywhere on the animal appear to be ciliated, on the legs as well as on 

 the other parts. 



Observations. — There were two specimens taken off the Fiji Islands that correspond 

 much with the one described, and which I consider to belong to the same species. The 

 chief distinctions between them exist in the length of the ophthalmopoda, their projection 

 upon long and slender stalks, and the greater length of the scaphocerite as compared 

 with the rostrum, which nearly corresponds in length with that in the specimen from 

 Japan, but differs in having three minute teeth on the upper margin. These however 

 are visible only in a lateral view and with increased magnifying power. 



In the Fiji specimens the hairs on the legs instead of being ciliated are smooth. 



The second pair of pereiopoda in both specimens has the chela broken off, and the 

 pleon has the third somite armed with a stronger tooth than in the Japanese specimen. 



Diaplwropus, 1 n. gen. 



Animal slender. Carapace not more than one-third the length of the animal, 

 anteriorly produced to a horizontal rostrum. 



Pleon smooth ; somites subequal. 



Telson tapering, slender. 



Ophthalmopoda robust. 



First pair of antennas biflagellate. 



Second pair furnished with a foliaceous scaphocerite ; flagellum long and slender (?). 



Mandible without a synaphipod. 



First pair of pereiopoda slender and terminating in a straight styliform dactylos. 

 Second pair robust, chelate. Third and fourth pairs short, simple, and terminating in a 



1 3/a!po{o?, different ; ttowj, foot. 



