Cumacea: 9. Leuconidae, 1. LeucoQ 65 



surrounded by stiff setae springing from the pseudorostral margin. Perae- 

 opod 1 rather robust, 5*'! and B**^ joints equal, 7^^ about one-third as long 

 as either. Peduncle of uropods shorter than the subequal rami, eudopod with 

 pt joint nearly three times as long as 2^\ with 5 spines on medial margin, 

 2"*^ joint with 3 spines and at apex a spine and a stout plumose seta. 

 L. 9 juv. (Ireland) 3*85 mm, 9 with marsupium (Mediterranean) 2*7 mm. 



W. coast of Ireland; depth 699 ni; Mediterranean, near Capri; depth 100 — 1100 m. 



2. L. tenuirostris O. Sars 1887 L. t., G. O. Sars in: Rep. Voy. Challenger, 

 V.19 pars 55 p. 33, 38 t. 5 f. 1 — 4 [ 1905 L. t., Caiman in: Sci. Invest. Fish. Ireland, 

 1904 app. 1 p. 20 I 1908 L. t., Zimmer in: Ergeb. Tiefsee-Exp., v. 8 p. 177, 178. 



General form very slender. Pseudorostral lobes slightly upturned, 

 tapering to subacute apices for a length exceeding half that of the rest of 

 the carapace; antero-lateral corners little produced but acute, preceded by a 

 small sinus between denticles. Carapace compressed, with median carina 

 having 7 teeth along the front half, and front half of lower margin den- 

 tate. Fifth pedigerous segment not wider than the pleon, in which the 

 5th segment is very long, the telsonic segment short, almost pentagonal, 

 forming an obtuse triangle between the bases of the uropods. Antenna 1, 

 accessory flagellum not wart-like, its one joint as long as first of principal 

 flagellum. Peduncle of uropod as long as the endopod, in which the somewhat 

 tapering first joint has 5 spines on the medial margin, the slender 2'^'^ joint 

 a little more than half as long has 4 spines, the apical the largest; the 

 exopod only reaches half way along the 2"*^ joint of the endopod. L. 9 juv. 

 about 10 mm. 



N. Pacific, lat. 36o 10' N., long. 178^ E.; depth 3750 m. 



3, L. nasieoides Lilj. 1855 L. «., W. Liljeborg in: Ofy. Ak.Forh.. v. 12 p. 122 | 

 1869 L. H., G.O.Sars in: Nyt Mag.Naturv., v. 16 p. 345 | 1872 L. n., G.O.Sars in: Forh. 

 Selsk. Christian., 187 1 p. 270 \ 1879 L. n.. G. O. Sars in : Arch. Naturv. Kristian., vA p. 15, 22 j 

 1879 L. M., A. M. Norman in : Ann. nat. Hist., ser. 5 v. 3 p. 72 | 1879 L. nasicoidis, S. I. Smith 

 in: Tr. Connect. Ac, v. 5 p. 115, L. nasieoides. p. 125, 129 | 1886 L. nasieoides, G. 0. Sars in : 

 Norske Nordhavs-Exp., v. 6 nr. 15 p. 19 \ 1887 L. n., H. J. Hansen in: Vid. Meddel., v. 39 

 p. 199 1900L.7Z., G.O.Sars, Crust. Norway, u 3 p. 31 t. 23 | 1900 L. ?j. (part.), Zimmer in : 

 Eauna arctica, v. I p. 411,416 | 1901 L. «., Ohlin in: Bih. Svenska Ak., t;. 26 nr. 12 p. 41 | 

 1908 L. n.. Zimmer in: Ergeb. Tiefsee-Exp., v.8 p. 177, 178 | 1911 L. «., Stappers in: 

 Camp. arct. Orleans, Crust. Malac. p. 102 t. 4 f. 5, 7 | 1912 L. n.. Caiman in: P. U.S. 

 Mus., v.il p. 619. 



9 . Pseudorostral lobes moderately produced horizontally to narrowly 

 truncate apex; lateral truncation denticulate; antero-lateral corners triangular, 

 the lower margin behind them serrate for half its length. Median carina of 

 carapace serrate from front to hind margin, frontal lobe having also 3 den- 

 ticles on each side. Telsonic segment short, pentagonal, triangularly pro- 

 duced between bases of uropods. Antenna 1, 3"^ joint shorter than 2^^. 

 Peraeopod 1, 6^^ joint much shorter than 5^'^ Peraeopod 2, 3*^ joint wanting. 

 Peduncle of uropods a little shorter than the subequal rami; first joint of endo- 

 pod more than twice as long as 2"*^, carrying 9 spines on the medial margin, 

 where the 2"*^ has 5 followed by a long one at the apex. Colour yellowish 

 white. L. 6 mm. 



(J. More slender than 9. Pseudorostral lobes transversely truncate, 

 "with 2 denticles; antero-lateral corners obtuse-angled. Carapace smooth 



Das Tierreich. 39. Lief.: T. R. R. Stebbing, Cumacea. 6 



