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



peduncles of second pair equal in length to the shorter of the two rami ; third pair 

 reaching much further back than the second, peduncles much shorter than the rami ; 

 rami lanceolate, spined on both sides, setose on the inner, the outer and under longer 

 than the sharply pointed inner ramus, and ending in a long naU. Some or all of the 

 borders of the rami are minutely pectinate ; some of the lateral spines show an oblique 

 striation, and are finely denticulate. 



Telson very long, narrow, tapering, produced far beyond the peduncles of the third 

 uropods, cleft for nearly five-sixths of its length, the inner part of each apex produced to 

 a fine point beyond the outer part of the apex, and having in the cavity a spine with 

 accessory thread and a cilium ; there are five spines along each lateral margin. The 

 telson, like many other parts of this species, is exceedingly thin and transparent. 



Length. — The specimen in its coiled position was seven-twentieths of an inch long. 

 The smoothness of the side-plates of the first two peraeon-segments suggests that 

 the much larger side-plates which follow are in their natural position in relation to the 

 head and front legs, and from this it may be inferred that the coiled position of the dead 

 specimen would not be unnatural for the living animal. 



Locality. — It was labelled as taken in the tow-net, ofi" Tahiti, the 2nd of October, 

 1875. This corresjionds with Station 279 ; lat. 17° 30' 26" S., long. 149° 33' 45" W.; 

 depth, 420 fathoms ; bottom, volcanic mud. One specimen. 



Remarks. — The specific name refers to the jDlace near which it was taken. 



In regard to the antennae, side-plates and pleon, and in some other points, this species 

 shows some affinity with the species of Cyj^hocaris ; in regard to the side-plates and 

 slenderness of the gnathopods it agrees with Lysianassa (?*) cymba of Goes, but differs 

 from that species in not having a rostrum and in having a long, narrow, much-divided 

 telson instead of one broadly oval with the apex whole. 



Genus Euonyx, Norman, 1867. 



The original definition of the genus is : — 



"Difi'ering from Anonyx in having the first gnathopods chelate, and the second 

 stronger than the first, subchelate, nail large and strong. Posterior uropods two- 

 branched. Telson cleft." 



For the inclusion of the present species, the words " nail large and strong " must be 

 excised ; on the other hand it might be well to include in the definition the statement 

 that the side-plates of the first perteon-segment are short and small. 



