1362 THE VOYAGE OF H.M.S. CHALLENGER. 



Phronimella elongata, Claus 1 (PI. CLXIIL). Specimens A, B. 



Male. — The first two (coalesced) segments of the peiseon not longer than the third 

 but deeper ; the seventh segment longer than any of the preceding, distally narrowed ; 

 the first three segments of the pleon deeper than the last of the perseon, the first the 

 longest, the second the deepest, the third the shortest, the postero-lateral angles of 

 all jjroduced into a minute tooth, the lower margin in the second and third very 

 convex. 



Eyes answering the generic description. 



Upper Antennas. — The peduncle not very long, the first joint the widest, wider than 

 long, the two following joints about equal to one another, together not so long as the 

 first ; the first joint of the flagellum of great length, longer than the five following slender 

 joints together, narrowing a little distally, the apex produced to a point beyond the 

 second joint, the whole breast covered with a brush of long slender filaments ; the fourth 

 joint longer than the second or third, the fifth longer than the fourth, the two following 

 each shorter than the fifth, all bordered with short filaments at intervals ; the remainder 

 of the flagellum missing. 



Lower Antennas. — Gland-cone projecting from the wall of the head, third (first free) 

 joint of the peduncle much narrower than the peduncle of the upper antennae, longer than 

 broad, a little widened distally, fourth joint shorter, fifth joint narrower than fourth, 

 narrowing distally, as long as the third ; flagellum abruptly narrower than the peduncle, 

 very long and filiform, containing in the specimen examined about twelve elongate 

 joints carrying slender filaments, the last joint ending bluntly. 



First Gnathopods. — The first joint longer than the others together, the margins 

 smooth and nearly parallel, the muscles occupying only a small space at the distal end 

 of the joint ; the second joint longer than broad ; the third not longer than the second, 

 distally a little projecting but not produced behind the fourth joint, its convex margin 

 being here faintly scabrous, and carrying one hair or spinule ; the wrist elongate, longer 

 than the two preceding joints together, equal in length to the hand, widening a little 

 distally, the front margin almost straight, the hind margin a little before the apex 

 produced into a narrow tooth carrying a spinule, the arched cavity between this and the 

 apex being scabrous ; the hand narrow, slightly bent, carrying a few hairs or spinules, the 

 dactyloptera at its extremity of great tenuity, reaching to the middle of the finger ; 

 the finger small and curved, not half the length of the hand, narrowing rather abruptly 

 near the base and again at the insertion of the slender nail ; the figure gives a ventral 

 view, in which the finger appears almost straight ; the dactyloptera are difficult to see in 

 full ; they appear to be oval, smooth-edged, with longitudinal markings which may be 

 due to an optical effect of the transparent concave surface. 



1 The references for the species are practically the same as those already given for the genus. 



