170 Cumacea: 24. Nannastacidae, 3. Nannastacus 



2. N. suhmii 0. Sars 1887 N. s., G. 0. Sars in: Rep. Voy. Challenger, r. 19 

 pars 55 p. 9, 63 t. 10 f. 4, 5 (N. suhmi in: explanation of plate) | 1900 iV. s., T. Stebbing 

 in: Willej', Zool. Results, pars 5 p. 64 | 1904 N. s., Caiman in: Herdmau, Rep. Ceylon 

 Pearl Fish., v.2 p. 177 | 1905 iV. s., Caiman in: Siboga-Exp., nr. 36 p. 12 ] 1911 N. s., 

 Caiman in: Tr. zool. Soc. London, «. 18iv p. 354 | 1912 N. s., T. Stebbing in: Ann. 

 S. Afr. Mus., V. lOv p. 164. 



o . Form of body rather stout. Pseudorostral lobes obliquely upturned, 

 forming a narrow blunt-ended tube tipped with setules, antero-lateral margins 

 broadly concave, the lower corners sirongly produced, ending bluntly, serrate 

 below. Carapace setulose, without keels or spines (Sars), but perhaps with 

 medio-dorsal tooth or spine (Caiman), boldly arched till near the end which 

 carries a few small denticles. First 4 pedigerous segments very short, side- 

 plates evenly rounded, quite smooth. Pleon with a few very small denticles 

 on dorsal sm-face of each segment (G. 0. Sars), anterior pleon segments Avith 

 strong paired teeth on dorsal surface (Caiman). Eyes wide apart, each with 

 ." corneal lenses. Antenna 1 slender, accessory flagellum knob-shaped. Maxilli- 

 ped 3 and peraeopods 1, 2, with remarkably small exopods (G. 0. Sars), 

 maxilliped 3 with no trace of an exopod (Caiman). Peraeopods 3 — 5 subequal, 

 considerably longer than peraeopod 2, their 5*^ and 6^^ joints elongate. 

 Peduncle of uropods unusually short, exopod exceedingly small, though con- 

 sisting of two well defined joints, endopod rather elongate. Colour rather 

 pellucid, with a few dark brown patches, one low down on each side of 

 carapace, and a band on 5*^ pleon segment. L. about 2 — 2-6 mm. 



d. Less robust than 9 . Pseudorostral lobes little prominent, obtusely 

 rounded, antero-lateral corners less prominent, lower margin iiTegularly flexuous, 

 smooth. Carapace with dorsal line almost horizontal. Pleon segments quite 

 smooth. Eyes much larger than in Q . Antenna 2 scarcely reaching beyond 

 3*^ pleon segment, joints of flagellum very long and thin. Peraeopod 1 with 

 .5*^ and C)^^ joints slender, subequal, the 7**^ shorter. Endopod of uropods 

 even more elongate than in the Q . Colour much darker and more extended. 

 In both sexes a dark baud on i*'^ joint of maxilliped 3 and peraeopod 1. 



Off Samboanga, Philippine Islands; surface. 



3. N. gibbosus Calm. 1911 N. g., Caiman in: Tr. zool. Soc. London, u. 18iv 

 p. 341,355 t. 33 f. 16—21. 



Pseudorostral lobes short, truncate, meeting in middle line below branchial 

 orifice, antero-lateral margin deeply concave, lower corner produced, triangular, 

 sometimes with one or two denticles at apex. Carapace variable, uneven, 

 setose, with depression between branchial bosses, a small boss behind each 

 eye. a denticle sometimes behind the eyes and one or two on rearward dorsal 

 elevation. Pedigerous segment 1 represented only by side-plates, those of 

 the following segments expanded and rounded, segments 2 and 5 sometimes 

 Avith medio-dorsal denticle, such as also occurs sometimes on pleon segment 1. 

 Eyes prominent, dark. Antenna 1, 3*^ joint longer than 2'^'^, flagellum with 

 minute terminal joint. Maxilliped 3 without exopod, 2'^'^ joint rather short, 

 apical process not long. Peraeopods 1, 2, with well developed exopods, 

 2"'^ joint of peraeopod 2 dilated, 6^^ joint longer than P\ 1^^ twice as long 

 as 6^^: in 5**1 pair 5*i' joint fully twice 'i^^ and subequal to 7*^ joint. Endo- 

 pod of uropods nearly thrice length of peduncle and fully 8 times as long 

 as exopod, but apical spine of exopod considerably longer than that of 

 pjidopod. L. o P8 mm. d unknown. 



Gulf of Siam, 4—9 m. 



