164 Cumacea: 23. Heteroleucoaidae, 1. Heteroleucon, 24. Nanuastacidae 



1. Gen. Heteroleucon Caiman 



1907 Heteroleucon (Sp. un.: H. akaroensis), Caiman in: Tr. zool. Soc. London, 

 t). 18i p. 32, 34. 



For the single genus the characters of the family for the pre- 

 sent suffice. 



1 species. 



1. H. akaroensis Calm. 1907 H. a., Calmau in: Tr. zool. Soc. London, v.l8i 

 p. 34 t. 8 f. 11— 23. 



9 . Pseudorostral lobes directed obliquely upwards with upper margin 

 straight, apically acute; antero-lateral corners preceded by a double denticle 

 and small rounded sinus, then beginning a seiTate division of the lower 

 margin. Median line of carapace having the carina serrate with 8 — 10 teeth 

 in front half and one larger tooth close to hind margin. Telsonic segment 

 little produced between bases of uropods. Antenna 1 with first 2 joints 

 stout, S*^ shorter and narrower, flagellum 2-jointed, accessory 1-jointed. An- 

 tenna 2 three-jointed, with 2 setae on the P* joint. Maxilliped 1 with 

 only 2 small papilliform branchial sacs. Peraeopod ] with 2^^*^ joint shorter 



Fig. 113. Fig. 114. 



H. akaroensis (9) Caiman, antenna i. H. akaroensis (9) Caiman, antenna 2. 



than rest of limb. Peraeopod 2 with very short 3^ joint. Peduncle of uro- 

 pods rather shorter than the subequal rami, endopod with about 10 spines on 

 medial margin and a strong, dorsally curved, apical spine. L. 2*75 mm. 



d. Pseudorostral lobes very short, horizontal, apically rounded; antero- 

 lateral corners broadly rounded and serrated. Median line of carapace smooth, 

 except for one or two small seiTations anteriorly. Antenna 1 with 3-jointed 

 flagellum. Antenna 2 with flagellum very short, not longer than peduncle, 

 9-jointed. Peduncle of uropods little more than half as long as the rami. 

 L. 1*65 mm. 



New Zealand, Akaroa Harbour, depth 11 m (both sexes), Lyttleton Harbour, 

 depth 2 — 9 m (females). 



24. Fam. Nannastacidae 



1866 Nannastacidae, Bate in: Zool. Rec, v. 2 p. 329 | 1878 & 1879 Cumellidae, 

 G. 0. Sars in: Arch. Naturv. Kristian., v. 3 p. 466; v. 4: p. 92 | 1880 C, Kossmann, 

 Reise Roth. Meer., Malac. pars 2 p. 90 | 1887 C, G. 0. Sars in: Rep. Voy. Challenger, 

 V. 19 pars 55 p. 62 | 1893 Nannastacidae, T. Stebbing in: Int. sci. Ser., v. 74 p. 305, 

 312 I 1895 N, H. J. Hansen in: Ergeb. Plankton-Exp., v.2 G. c. p. 59 | 1897 Cumellidae, 

 Ehrenbaumin: Wiss. Meeresunters., v.2i p. 419 | IdOO Nannastacidae, G. 0. Sars, Crust. 

 Norway, v.3 p. 79 | 1900 N., Zimmer in : Fauna arctica, v. 1 p. 428, 431 | 1900 N, T. Stebbing 

 in: Willey, Zool. Results, pars 5 p. 611 | 1904 N., Caiman in: Herdman, Rep. Ceylon 



