64 



Cumacea: 9. Leuconidae. 1. Leucon 



- Antenna 1 with accessory flagellum longer than 1st 



) joint of principal. 11. L. heterostylis 



I Antenna 1 with accessory flagellum not longer than 

 I 1st joint of principal — 13. 



/ Telsonic segment greatly produced between the 



) uropods 12. L. longirostris 



1 Telsonic segment only moderately produced between 



I the uropods 13. L. kalluropus 



/ Uropod with 2iid joint of endopod not broader at end 



I than its apical spine 14. L. pallidas 



I Uropods with 2iicl joint of endopod broader at end 

 ' than its apical spine • — 15. 



j Carapace with median serrations continuous throughout 15. L. serratus 

 15 -c Carapace with median serrations not continuous 

 ( throughout — 16. 



j Eyelobe small but distinct 16. L. kerguelensis 



\ Eyelobe rudimentary — 17. 



( Pseudorostrum horizontal — 18. 

 17 



\ Pseudorostrum bent upwards — 19. 



{Frontal lobe with 3 denticles on each side; median 

 serrations not limited to first half of carapace . 17. L. assimilis 

 Frontal lobe without lateral denticles; median ser- 

 rations only on first half of carapace 18. L. acutirostris 



i Uropods with exopod only a little longer than the 



19 { peduncle 19. L. sagitta 



I Uropods with exopod much longer than the peduncle 20. L. vanhoefFeni 



1. L. siphonatus Calm. 1905 L. s., Caiman in: Sci. Invest. Fish. Ireland, 

 1904 app. 1 p. 19 t. 1 f. 2—4 1 1906 L. s., Caiman in: Mt. Stat. Neapel, v. 17 p. 416 t. 27 

 f. 9 I 1908 L. s., Zimmer in: Ergeb. Tiefsee-Exp., v. 8 p. 177. 



Pseudorostral lobes well advanced, slightly upturned, apically rounded, 

 with teeth on the dorsal and apical margins in the 9 only, the border between 



Fig. 33. 



L. siphonatus Caiman (? juv.). 



the apex and the antero-lateral tooth having 2 emarginations separated by 

 a serrate prominence and introduced by a strong subapical tooth; the lower 

 border behind the antero-lateral tooth serrate. In the 9 the frontal lobe has 

 one or two teeth at its apex. Anteriorly the sides of the carapace are 

 sprinkled with denticles. Antenna 1, 3"^ joint longer than 2"^, flagellum 3-jointed, 

 the 1-jointed accessory not wart-like but nearly equal in length to V^ joint 

 of principal flagellum. 1^* maxillipeds, with the branchial siphon formed by 

 the exopods capable of protrusion to a distance greater than length of carapace, 



