1352 THE VOYAGE OF H.M.S. CHALLENGER. 



with a very fine but obvious pectination ; in the male specimen this ramus was smaller, 

 and on one side of the animal little more than a tubercle, though on the other side it was 

 more than half the length of the outer ramus and apically acute. 



Telson wider than deep, the curved distal margin scarcely projecting between the 

 bases of the third uropods, the texture so thin as to make its outline difficult to 

 observe. Guerin says that the telson is triangular, but this may refer to the profile view, 

 as in the dorsal view he makes it curved ; in both views he draws the fifth and sixth 

 segments of the pleon as separate, and he treats them as distinct in the description ; 

 there can be little doubt that this is an error of observation. 



Length of the female specimen half an inch, of the male seven-twentieths of an 

 inch. 



Locality. — Station 245 ; June 30, 1876 ; between Japan and Honolulu ; lat. 36° 23' 

 N., long. 174° 31' E.; surface temperature, 69°. Two specimens, female and young 

 male. 



Remarks. — From the same locality there are two other specimens of Phronima, very 

 small, one, by more swollen upper and the budding lower antennae, shown to be a young 

 male, this scarcely a quarter of an inch long, and the other about one-fifth ; in each, the 

 fourth joint of the third perseopods is distally wide, with a narrowly produced incurved 

 apex to the front margin, and two little subecpial teeth on the distal margin ; the fifth 

 joint bulges a good deal where its inner or front margin meets the cavity of the fourth 

 joint's distal margin. 



In Guerin's figure of this species the gnathopods are represented as linear, without 

 any prolongation of the wrist. Milne-Edwards, probably judging only by the figure, 

 says, " pates des deux premieres paires greles et sans elargissement vers le bout." There 

 can be little doubt, however, that Guerin represents them as seen edgewise, and that he 

 left them undescribed because he had not made out the details. In the Brit. Mus. 

 Catal. Amph. Crust., pi. 51, Gudrin's figure is reproduced, and close to it is placed a 

 figure marked ii, as if to represent the second gnathopods ; but this figure has not 

 really anything to do with Phronima atlantica, having been accidentally transferred from 

 Guerin's Oxycephalus oceanicus. In regard to specimens from the " Atlantic, latitude 

 7° or 8° north, and longitude about 24° west," Dana only says, "the figure of Guerin 

 represents our specimens correctly in most respects. The moveable finger of the large 

 hand has a low tooth on its inner side, one-third of the distance from its base to its apex ; 

 and the immoveable finger is longer, with a prominent angle near the articulation with 

 the moveable finger." A species named Phronima spinosa by Bovallius in 1887, found 

 in " tropical parts of the Atlantic," does not seem to differ much from Guerin's except 

 that it is said to have the first joint of the fifth peraeopods nearly twice as long as that of 

 the fourth pair. 



