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Stat. 279. January 1 1 13. Rumah-Kuda-bay, Roma-island. 36 m. Mud and sand. 1 specimen, 



probably a male, and 1 egg-bearing female. 

 Stat. 313. February 14/16. Anchorage East of Dangar Besar, Salch-bay. Depth up to 36 m. 



Sand, coral and mud. 2 specimens, one of which with eggs. 



Probably a new species, closely related to A. rapax de Haan = A. distinguendus de Man 

 from Japan and to A. rapax Cout. 1905 from the Laccadive Archipelago. It belongs to those 

 species of the Brevirostris group, in which the upper border of the large chela bears n o 

 transverse groove near the articulation of the dactylus and in which the dactylus of the 

 small cheliped of the male is not Ba/ae7iiceps-sha\-)ed, at least when the large specimen from 

 Stat. 279 is really a male. This specimen, which is larger than the others, is 22,5 mm. long. 

 This species differs from A. distinguendus by its mtich smaller size, unfortunately Coutièke 

 does not mention the length of the male referred by him to A. rapax (Alpheidae Mald. and 

 Laccad. Archip. 1905, p. 905). 



Rostrum acute, almost reaching to the middle of first antennular article, continued in a 

 carina, which, rather acute between the orbital hoods and separated from them by narrow, deep 

 grooves, becomes, posteriorly to the hoods, obtuse, gradually lower and more inconspicuous, 

 though it can be foliowed almost to the middle of the carapace. 



Second antennular article little (about one-fourth) longer than the visible part of the 

 first and 2,5-times as long as thick; third article about half as long as the second. Stylocerite 

 foliaceous, ending in a small spinule that reaches to the end of first antennular article. 



Antennal peduncle as long as that of the upper antennae, basicerite with a small spinule 

 on the lower margin, which spinule hardly reaches as far forward as the rostrum. The scaphocerite 

 that extends beyond the antennular peduncle almost by the whole length of third article — in 

 the egg-bearing female from Stat. 313 even by slightly more than this article — is 3-times 

 as long as broad; the outer margin is very slightly concave and the terminal spine extends 

 but for a short distance beyond the blade. Telson twice as long as broad anteriorly, while the 

 width of the posterior margin is a little less than one-third of the length ; swimmerets a little 

 longer than the telson. 



Of the external maxillipeds that reach as far forward as the antennal peduncle, the 

 terminal joint has a slender form, being 5-times as long as broad; its margins are beset with 

 long setae, those at the tip being one and a half as long as the joint itself; the penultimate 

 joint is almost half as long as the terminal joint and one and a half as long as thick. 



The merus of the large cheliped of the male from Stat. 279 is 3,1-times as long as 

 broad, the upper margin ends in a small spinule, as in Spence Bate's A. rapax (Report 

 Challenger Macrura, PI. 99, fig. 1 k), while the infero-external margin is very finely serrulate 

 along its whole length; the infero-internal margin bears 4 small, movable spinules and ends 

 in a small, acute tooth. Chela similar to that of Bate's A. rapax, but its form appears more 

 slender, because it is almost four times as long (7,8 mm.) as high (2,1 mm.); palm 

 compressed, half as thick as high. The upper border of the palm which is almost twice as 

 long (5 mm.) as the fingers, is somewhat flattened, the inner margin is fringed with hairs from 

 the tip of the dactylus to the carpal articulation and there is n o transverse groove near the 



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