1532 THE VOYAGE OF H.M.S. CHALLENGER. 



hind margin does not reach quite so low as that of the front, while in the other the two 

 apices are on a level ; the produced apex of the third joint is rather less instead of rather 

 more than half the length of the fourth joint ; the finger is minute. 



Fifth Perssopods differing chiefly from those of the species just mentioned by having 

 only two joints, the second or terminal joint minute, a little longer than broad, directed 

 backwards, the front margin convex, the hinder nearly straight, with a small incision 

 high up, probably indicating an original division of the joint into two. The shape of the 

 male organs on the ventral surface of the seventh perseon-segrnent is shown in the figure 

 prp 6 . 



Pleopods. — The spines as in the other species ; the joints of the rami about fifteen in 

 number, the first joint not very long. 



Uropods. — The first two pairs as in Parapronoe claxisi, the pectination here seen to 

 be continued, though not strongly, up the inner margin of both rami of the second pair ; 

 the outer ramus of the third pair almost as Ions; as the inner, with two or three little 

 indents on the outer margin, the inner margin pectinate except near the base and at the 

 apex ; the inner ramus with smooth outer margin, the lower half of the inner pectinate 

 with little close-set teeth, not as in Parapronoe clausi with comparatively large teeth 

 wide apart. 



Telson twice as long as the breadth at the base, almost as long as the third uropods. 



Length, to the end of the second pleon-segment, a little over two-fifths of an inch. 



Localities. — Pacific, between Papua and Japan, surface. One specimen, male, to 

 which the above description applies. 



North Atlantic, between Tenerife and St. Thomas, West Indies ; surface. One 

 specimen. 



April 29, 1876, North Atlantic; lat. 18° 8' N., long. 30° 5' W. ; surface, night; 

 surface temperature, 73° 7. One specimen, male. 



April 28, 1876, North Atlantic; lat. 17° 47' N., long, 28° 28' W. ; surface ; surface 

 temperature, 73°'5. One specimen. 



Atlantic, surface. One specimen. 



Remarks. — The specimen taken April 29, 1876, measured about seven-tenths of an 

 inch in length ; in the fifth peraeopods the distal end of the first joint is rather flattened 

 than rounded, not at all produced, and is followed by tiro minute joints, very narrow, 

 about equal to one another in length ; the postero-lateral angles of the third pleon- 

 segment are a little outdrawn. Claus figures the fifth peraeopods with only one appen- 

 dicular joint, but this character is probably variable; the relative lengths of the joints 

 of the lower antennae are also most likely subject to some variation. The resemblance 

 in almost all details is so exact between the Pacific and Atlantic specimens, that the very 

 small points of difference do not seem to justify specific distinction. 



