1024 THE VOYAGE OF H.M.S. CHALLENGER. 



as in the preceding joint being finely pectinate ; the three last-mentioned joints have on 

 the surface several transverse rows of slender setse, which, when the animal is in liquid, 

 stand out on either side and give a feathered appearance to the limb ; these setse are 

 numerous at the apes of the fourth joint ; the finger is short and slender. In the 

 figure the first two pairs of peragopods are represented facing forwards, as they 

 happened to be in the specimen, but these long slender appendages sway about in all 

 directions, and the normal position of the limbs is, therefore, assumed in the use of 

 the terms — front margin and hind margin — in the description. 



Second Perseopods. — Branchial vesicles simple, much larger than the preceding pair, 

 four-tenths of an inch long. Limb two inches long ; first joint nearly as long as the 

 third and fourth together, fourth a little longer than the third, fifth decidedly longer 

 than the fourth, narrowed at the apex, armed as in the preceding pair, the distal part 

 carrying a line of gland-cells ; finger small, acute or almost so, a little curved. 



Third Perasopods. — Branchial vesicles rather larger than the preceding pair. Limb 

 all but three inches long ; the first joint the longest, the second very short, the fourth 

 longer than the third, and the fifth than the fourth, the slender fifth joint not much 

 shorter than the first ; the first, third, and fourth joints serrate or dentate on three 

 edges, the fifth along the front margin ; the fifth joint distally having a line of gland- 

 cells ; the finger small. 



Fourth Perzeopods. — Branchial vesicles rather larger than the preceding pair. 

 The limb nearly two inches and a half long, the armature and relative lengths of the 

 joints nearly as in the preceding pair. 



Fifth Pereeop>ods. — Limb an inch and two-tenths long ; the first joint wider above 

 than below instead of the reverse as in the other limbs, as long as the third and fourth 

 joints together, the fourth scarcely longer than the third ; the fifth longer than the 

 fourth, narrowest at the base, not narrowing distally, except where the finger is hinged, 

 behind which on either side it is jtroduced into a little sharp spinous process, whde in 

 front the distal end of the joint forms a kind of short oblique jjalm-margin with four 

 distant teeth ; the small finger is slightly bent, comparatively thick for the first half, 

 the remainder narrow, acute ; the inner margin of the thick part has a minute denticle. 

 In these and in the first and fourth perseopods, gland-cells probably occur at the distal 

 end of the fifth joint, but they were not distinctly observed. 



Pleopods. — The first pah- about half an inch long, the peduncles rather shorter than 

 the rami ; the coupling spines minute, with narrow apex and six or eight retroverted 

 teeth on each margin ; there is no cleft spine, but the long and large first joint of 

 the inner ramus carries numerous feathered setae, in the first pair having as many as 

 twenty-four on the inner margin ; the outer ramus has twenty-seven setse along the 

 outer margin of the first joint ; the joints of the inner ramus in the first pair are 

 twenty-one, of the slightly longer but narrower outer ramus twenty-four. 



