8 



aa. Median ridge of the gastric region carrying behind the two rostral 

 teeth four spines, the penultimate of which is double. 



b. The first three terga culminate in a spine trispiuosa (de Man) 



db. The first four terga culminate in a spine. Terga smooth . . phosphorus (Alcock) 

 bbb. The first five terga culminate in a spine. Terga not smooth . andamanensis (Alcock). 



Like as of the genus Polycheles, so also of Stercoinastis no species were known to inhabit 

 the Indian Archipelago before the discoveries of the "Siboga"; probably still one or two other 

 forms will afterwards prove to occur also in these seas, so e. g. Siereoin. cerata (Alcock) or 

 Stereo7fz. Helleri (Sp. Bate). 



One of the specimens of Stercoin. a7idamancnsis (Alcock) was taken at a depth of 1093 

 fathoms, nearly at the same depth (1043 fathoms), at which the type of this species was obtained; 

 the other specimens were gathered in less deep water. 



I. Stereomastis sculpta (S. I. Smith). 



Polycheles sadptus S. I. Smith, in: Proc. U. S. Nat. Museum, Wash., Vol. II, for 1879, March 



1880, p. 346, PI. VII. 

 Pentaclieles sculptus S. I. Smith, in : Bull. Mus. Compar. Zoology Harvard College, Cambridge, 



Vol. X, N" I, 1882, p. 23, Pis. Ill and IV and in: Report of the Commissioner of Fish 



and Fisheries for 18S2, Wash. 1884, p. 358. 

 Polycheles sculptus M. CauUery, in: Annales de I'Universite de Lyon, Paris, 1896, p. 385. 

 Pentaclieles sculptus A. Alcock and A. R. S. Anderson, in : Annals Mag. Nat. Hist. Ser. 7, 



Vol. Ill, 1899, p. 289. 

 Polycheles sculptus A. Alcock, A descriptive Catalogue of the Indian Deep-Sea Crustacea 



Decapoda, Macrura and Anomala in the Indian Museum, Calcutta, 1901, p. 170. 

 Polycheles sculptus Th. R. R. Stebbing, South African Crustacea, Pt. II, Cape Town, 1902, p. 36. 

 Polycheles sculptus A. Senna, in: Bull. Soc. Entom. Ital. XXXIV, 1903, p. 338. 

 Polycheles sculptus C. M. Selbie, in: Fisheries, Ireland, Sci. Invest. 1914, I. [1914], p. 18, 



PL II, figs. 1—9. 

 Pentaclieles spinosus A. Milne Edwards, in: Bull. Mus. Compar. Zoology Harvard College, 



Cambridge, Vol. VIII, 1880, p. 66. 



Stat. 18. March 18. 7°28'.2S., II5°24'.6E. 10 18 m. Bottom fine grey mud. i male. 

 Stat. 211. September 25. 5°4o'7S., I20°45'.5E. 1158 m. Bottom coarse grey mud, superficial 

 layer more liquid and brown, i young male. 



The male from Stat. 18, which is almost adult, closely agrees with Smith's minutely- 

 detailed description of 1882. The external maxillipeds reach as far forward as the antennular 

 peduncles: it is no doubt a mistake, when Smith (I.e. p. 27) writes, that they "reach, when 

 extended, nearly to the bases of the peduncles of the antennulae", for in his figure, Plate IV, 

 fig. I, they appear just as long as in the present specimen. The i^' legs are wanting. The 

 merus of the legs of the 2"*^ pair reaches to the upper carina on the ventral region of the carapace, 

 that does not extend to its postero-lateral angle ; according to Smith the merus of these legs 

 should reach to the edge i. e. to the lateral margin of the carapace, but his specimens were 

 older and larger. This specimen does not show, except the spine of the eye-stalk, the pecu- 

 liarities of Faxon's variety pacifica^ but completely agrees with the individuals observed in the 

 Arabian Sea. The spines in the mid-line of the carapace are (the two rostral spines included) : 



