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



laterally produced to a narrow point, from the extremity of which the first pair of 

 pleopoda proceeds ; the second, third, and fourth somites are of similar length, and have 

 the coxal plates developed in a slightly squamous form, and carry the pleopoda attached 

 to the inner wall of the margin. The fourth somite is slightly longer than the preceding, 

 and has the coxal plate not developed in a squamous form, but as a process near the 

 posterior extremity, to which the pleopod is attached. The fifth somite is slightly 

 shorter than the fourth but resembles it in form. The sixth is nearly as long as the 

 preceding two, is considerably compressed laterally, and carries the sixth pair of pleopoda 

 at its posterior margin, which combine with the telson to form the rhipidura. 



The ophthalmopoda are stout and cylindrical ; the ophthalmus is not of larger diameter 

 than the stalk, and in this respect it differs from Kroyer's figure of Pasiphasa tarda, in 

 which the ophthalmus is larger than the peduncle. 



The first pair of antennae appears to be rather shorter than the carapace, but the 

 extreme ends of the flagella are broken off; the first joint is concave on the upper surface 

 for the reception of the ophthalmopod. 



The second pair of antenna? also has the flagellum broken, and carries a scaphocerite 

 that is broad at the distal extremity, armed with a small tooth on the outer distal angle, 

 and bears hairs upon the outer margin. 



The oral appendages have not been examined, as the specimen is unique and not very 

 perfect. 



The second pair of gnathopoda is pediform, but terminates in an obtuse extremity, 

 which reaches nearly as far as the distal extremity of the scaphocerite. 



The first pair of pereiopoda is shorter and more robust than the second, it has. the 

 propodos but little longer than the carpos and slightly stouter ; the fingers are stout at 

 the base, slightly curved, and pass each other at their apices. The second pair is much 

 longer than the first, each joint being slightly longer relatively than the corresponding 

 joint of the first pair ; the propodos is much longer and terminates in a pollex and 

 dactylos that are longer, more slender, sharper, and slightly curved. The three posterior 

 pairs are short and slender, the last two being subequal and shorter than the third 

 pair. 



The pleopoda are connected with the respective somites at the lateral margins, and are 

 not remarkably long. 



The telson is a little shorter than the lateral branches of the rhipidura. 



FainUy Oodeopidj:. 



Carapace short, anteriorly produced to a long horizontal rostrum. Pleon long, 

 generally armed with teeth. Ophthalmus long, ovate. First pair of antennae biflagellate. 

 Second pair furnished with a scaphocerite and a slender flagellum. Mandible without a 



