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



male (PL XLI. fig. 3) an ang-ularly-curved hook and five setae, two long and three short. 

 In other respects the animal does not appear to present any special difi"erentiations of 

 structure. Its length is l-16th to 1-llth of an inch (li55 mm. to 2*3 mm.). 



Only three or four examples have been found, and I am by no means sure that the 

 forms which I here refer to the male and female of the same species may not prove to be 

 specifically distinct. The following are the localities in which the species was taken : — 

 lat. 35° 11' N., long. 137° 8' E; lat. 35° 41' K, long. 167° 42' E. ; lat. 36° 44' S., 

 long. 46° 16' W., tow-net at trawl; depth 2650 fathoms. 



[PL XLI. figs. 1-10. 1 Anterior antenna and tentacle of female, 2 anterior antenna 

 of male, 2a portion of central seta more highly magnified, 3 secondary branch of posterior 

 antenna of male, 4 mandible and palp, 5 first maxilla, 6 second maxilla, 7 first foot of 

 male, 8 postabdomen, 9 dorsal angle and spine of male, 10 anterior ventral angle of 

 male. PL XLII. figs. 1-8. 1 Female with valves laid open and seen from below, 2 the 

 same seen from side (magnified 20 diameters), 3 portion of anterior margin of shell, 4 

 posterior angle and spine more highly magnified, 5 secondary branch of posterior female 

 antenna, 6 second maxilla, 7 first foot of female, 8 branchial appendage of first foot. 



Section CLADOCOPA. 

 Family Polycopid^, G. 0. Sars. 



Valves subequal, thin, not notched in front. Anterior and posterior antennae both 

 natatory, terminated by long setae, and having the basal portion large, stout, and mus- 

 cular ; the anterior pair simple, not geniculate ; posterior two-branched, both branches 

 natatory. Mandibles distinct, strongly toothed below ; palp short, neither pediform nor 

 clawed. Two pairs only of posterior limbs, scarcely pediform, the first natatory, the 

 second branchial. Abdomen terminated by two short numerously-clawed laminae. 

 Eyes wanting. No heart. Intestine forming a simple sac. 



Polycope, G. 0. Sars. 



Valves rounded, ventricose, corneo-calcareous. Forehead having no tentacle, but in 

 its place two ciliated setae. Anterior antennae three-jointed, last joint short, terminal 

 setae long- and slender ; terminal rami of posterior antennae unequal, one branch many- 

 jointed and similar in structure to that of Cypriclina, the other shorter and three-jointed. 

 Lower extremity of mandibles strongly inflexed, armed with a few small acute teeth ; 

 palp biarticulate, first joint stout, bearing externally a short, bisetose branchial appendage, 

 last joint narrow, beset with long plumose setae. Incisive portion of the first pair of 

 jaws small, forming a simple setiferous lobe ; palp very large, four-jointed, two-branched, 

 second joint bearing a long, narrow, and obsoletely-biarticulate branch, which is ter- 



