73 Cumacea: 9. Leuconidae, 1. Leucon 



scarcely an interruption from end to end, and in immature specimens (Caiman) 

 having 1 or 2 small denticles on each side of the frontal lobe. Telsonic 

 segment very short, produced and rounded triangular. Antenna 1, accessory 

 flagellum rudimentary. Peraeopod 2 with 3^ joint wanting or fused. Peraeopod 

 3 with three large lanceolate distally denticulate appendages on the 3^ joint 

 in d. Peduncle of uropods shorter than the rami or about equal to the 

 endopod exclusive of its spine-like terminal, which in immature specimens 

 is distinct from the trunk (Caiman), 2^^ joint apart from terminal less than 

 half as long as 1^*; exopod longer than endopod with the terminal included. 

 Colour pure white. L. o 4 mm, d 4*5 mm. 



Coast of Norway, depth 75 — 753 m; Spitzbergen, depth 2636 m; Kara Sea; Nova 

 Zembla. 90 m. 



15. L. serratus Norm. 1876 L. s. (nom. nud.), A. M. Norman in: Jeffreys inr 

 P. R. Soc. London, u 25 p. 212 | 1879 L. s., A. M. Norman in: Ann. nat. Hist., ser. 5 

 V. 3 p. 70 I 1900 L. s., Zimmer in: fauna arctica, v.l p. 418, 432 | 1908 L. s., Zimmer 

 in: Ergeb. Tiefsee-Exp., v. 8 p. 178. 



Pseudorostral lobes short, horizontal, triangular, with serrate edge; antero- 

 lateral corners produced forward and outward in wing-like form, the serrations 

 of lower margin forming about 10 teeth, the first 3 or 4 large. Median carina 

 of carapace boldly arched, serrate from end to end, teeth decreasing to the 

 rear. Peraeopod 1, 2"*^ joint with 7 spines on hind margin. Peduncle of 

 uropods not longer than 5*^^ pleon segment, endopod much shorter than 

 exopod, each of its joints with 5 spines on the medial margin, apical spine 

 two-thirds as long as the 2"^^ joint, L. 9 6 mm, d unknown. 



Davis Strait, lat. 50" 10' N., long. oO^ 25' W., depth 3200 m. 



16. L. kerguelensis Zimmer 1908 L. k., Zimmer in: Ergeb. Tiefsee-Exp., v.S 

 p. 178 t. 41 (6) f. 71, 72, t. 42 (7) f. 73—75. 



Body slender. Pseudorostral lobes short, subacute, slightly upturned. 

 Antero-lateral corners rounded, smooth. Carapace with a small but actual 

 eyelobe on which a smooth median carina takes its origin, ceasing a little 

 way to the rear of the frontal lobe. Antenna 1, flagellum 4-joiiited, the 

 1-jointed accessory about half as long as 1^*^ joint of principal flagellum. 

 Antenna 2 about reaching end of the body. Peraeopod 1 elongate, 2"*^ joint 

 in this and the 3 following pairs strongly developed. Peraeopod 3 having 

 the 3<^ joint equipped with 2 lanceolate appendages. Peduncle of uropods 

 closely fringed on medial margin mth. spines and plumose setae; the endopod 

 about equal to it in length, with 2^^^ joint half as long as the first, is little 

 more than three-fourths as long as the exopod. Colour white. L. d a little 

 over 5 mm. o unknown. 



Kerguelen, Gazelle Harbour. 



17. L. assimilis O. Sars 1887 L. a., G. O. Sars in: Rep. Voy. Challenger, 

 »;. 19 pars 55 p. 33, 34 t. 4 | 1908 L. a., Zimmer in: Ergeb. Tiefsee-Exp., r. 8 p. 177, 178. 



Near to L. nasim (nr. 6). Integument thin, pellucid, with no distinct 

 sculpture. Pseudorostral lobes not elongate; horizontal, subacute, oblique 

 margins denticulate and setulose, sinus denticulate; antero-lateral corners 

 triangular, lower margin denticulate for most of anterior half. Median carina 

 of carapace arcuate in front, densely denticulate and setulose, the 3 sub- 

 terminal denticles a little separated from the rest; eyelobe wanting, frontal 



