401 

 T j\.6. Alpheus acutocarinatus de Man. 



J. G. DE Man, in: Tijdschr. d. Ned. Dierk. Vereen. (2) Dl. XI, 1909, p. 104. 



Stat. 2. March 8. 7°25'S., II3°i6'E. Madura-strait. 56 m. Grey mud with some radiolariae. 



1 male, without the larger cheliped. 

 Stat. 19. March 19/21. 8°44'.5S., u6°2'.5E. Bay of Labuan Tring, West coast of Lombok. 



18 — 27 m. River-mud, coral, coralsand. 1 adult specimen, without small cheliped, 



probably a male, and a somewhat younger ova-bearing female, which has lost 



the larger cheliped. 

 Stat. 116. July 12. o°58'.5 N., I22°42'.5 E. West of Kwandang-bay-entrance. 72 m. Fine sand 



with mud. 1 adult, ova-bearing female. 

 Stat. 311. February 12 13. Sapeh-bay, East coast of Sumbawa. Depth up to 36 m. Mud and 



sand. 1 mutilated, young female. 



A new species of the Brevirostris group, related to A. macrosceles Alc. & Anders, from 

 the Bay of Bengal. The largest specimen, probably a male, is that from Stat. 19, which is 

 28 mm. long, the carapace, rostrum included, being just half as long as the abdomen. 

 Integument smooth and polished. Orbital region prominent, its width two-thirds that of the 

 anterior margin of the carapace. Rostrum acute, narrow, little longer than broad at base, 

 projecting straightly fonvard and reaching in most specimens to the middle of the visible part 

 of i st antennular article, in the female from Kwandang-bay, however, to the distal third. The 

 rostrum is continued in a prominent and sharp carina, that re ach es almost to 

 the posterior third of the carapace and that bears, immediately behind the 

 base of the orbital hoods, a small, obtuse tubercle or tooth; this tooth is 

 twice as far distant from the posterior margin of the carapace as from the 

 tip of the rostrum. That part of the rostral carina, which is situated before the median 

 tubercle, runs S-like, the interorbital portion, that in a lateral view is concealed by the orbits, 

 being concave ; the rostral carina is separated from the prominent, rounded and unarmed, orbital 

 hoods by deep, though narrow grooves and, at either side of the rostrum, the frontal 

 margin makes an obtuse angle with the anterior margin of the orbits. One observes, in the 

 mid-dorsal line of the carapace, quite posteriorly, a small, acute tubercle, little farther distant 

 from the raised line that runs parallel with the posterior margin than the latter from that line. 

 In the female from Kwandang-bay the rostruni appears a little less broad at its base than in 

 the other specimens. 



The pigment of the large eyes is well-developed. 



According to the figure 5 of Plate IX of the "Illustrations of the Zoology of the Investigator, 

 Crustacea", the 2 nd — 4" 1 abdominal pleura should be subacute in A. macrosceles \ in A. acuto- 

 carinatus, however, they are regularly rounded. The telson, about half as long as the carapace, 

 is twice as long as its greatest width anteriorly and tapers rather strongly, so that its 

 form is elongate; it suddenly narrows just in front of the middle, so that the distance 

 between the postero-lateral angles is only half as broad as the greatest width ; posterior 

 margin very prominent and strongly a reu at e. The upper surface is flattened, but 

 beyond the spinules it slopes down towards the lateral margins-, of the two pairs of spinules, 

 that are small, 0,24 — 0,28 mm. long, the anterior pair is situated just in front of the middle, 



269 



