REPORT ON THE COPEPODA. 101 



Pseuclotlialestris imbricata, n. sp. (PL XLII. figs. 1-8). 



Male. — Anterior antenna (fig. 1) eight-jointed, moderately setiferous, and provided 

 with a long and stout olfactory filament. Inner branch of posterior antenna (fig. 2) 

 small, two-jointed. Hand of the posterior foot-jaw (fig. 3) oval and armed with one seta 

 on the inner margin, terminal claw long and slender. Peduncle of the first pair of feet 

 (fig. 4) armed at the base of the inner branch with a crescentic series of stout teeth ; 

 first joint of the inner branch about five times as long as broad, setose on the outer and 

 having a single seta near the middle of the inner margin; second and third joints 

 together only about one-fifth as long as the first joint, terminal claw slender, nearly 

 straight, more than half as long as the first joint, and marginally pectinate ; outer branch 

 two-jointed, with very stout marginal and terminal spines. Inner branch of the second 

 pair (fig. 5) two-jointed, the second joint being composed of two coalescent joints; outer 

 branch three-jointed, with very large and stout marginal spines. Both branches of the 

 third and fourth pairs three-jointed (fig. 6). The fifth foot (fig. 7) has the two joints 

 nearly equal in size, inner segment of the first joint with three moderately long, 

 subequal, apical setse ; second joint quadrate, bearing five setse, one of which is much 

 longer than the rest. The joints of the abdomen (fig. 8) are short, and overlap very 

 much at the sides. The longest of the tail setse is about twice as long as the 

 abdomen. 



Only one specimen of this species was found, its characters being intermediate 

 between those of Dactylopus and Thalestris. The second, third, and fourth pairs of feet 

 agree closely with Thalestris, while the first foot, except as to the two-jointed outer branch, 

 is very similar to the same limb in Dactylopus. The female has not been seen. 



Habitat. — Betsy Cove, Kerguelen Island. 



Zaus, Goodsir. 

 Zaus, Goodsir, Ann. and Mag. Nat. Hist., 1845. 



Body broad and depressed ; head distinct from cephalothorax, rostrum broad and 

 truncated. Anterior antennae nine-jointed; posterior two-jointed, secondary branch 

 two-jointed. Mandibles strongly toothed, palp two-branched. First pair of feet two- 

 branched, its outer branch two-jointed, twice as long as the inner; inner branch two- 

 jointed, the second joint rudimentary; ovisac large, adpressed, single. Second, third, 

 and fourth pairs of feet with both branches three-jointed ; fifth pair foliaceous, two- 

 jointed. 



