triangular spine that reaches almost as far forward as the rostrum. Carpocerite extending- beyond 

 the antennular peduncle about by half the terminal joint ; the terminal spine of the scaphocerite, 

 the outer margin of which is nearly straight, reaches to the tip of the carpocerite, extends 

 backward to the distal extremity of 2 nd antennular article and overreaches with one-third or two- 

 fifths of its length the narrow extremity of the blade, which is as long as the antennular peduncle. 



As regards the outer antennae, the Red Sea type agrees with our specimen, but the 

 carpocerite has a somewhat less stout shape. 



Penultimate joint of external maxillipeds twice as long as thick at distal extremity, 

 terminal joint 1,75-times as long as the penultimate, 4-times as long as broad at its base. 



Merus of the large cheliped stout, 2,5-times as long as broad in the middle, distal ex- 

 tremity of the upper margin dentiform, obtuse ; infero-internal margin with 4 small, movable spinules 

 and at the distal extremity with a small, obtuse tooth. The larger chela closely resembles that 

 of the Red Sea specimen, but the lower margin is more conspicuously notched at the base of 

 the immobile finger and the extremity of the dactylus is not emarginate (de Man, 1. c. Fig. 6op"), 

 but slightly arcuate. 



The smaller cheliped is missing in both specimens-, the 2 nd legs of the typical species 

 have been described in my paper of 1S97, both are missing in the specimen from Lucipara-island. 



In the typical specimen the merus of the 3" 1 legs is 4,2 S-times, in that from Lucipara-island, 

 4,68-times as long as wide in the middle, appearing in the latter a little more slender; 

 carpus in the former 3,6-, in the latter 3,8-times as long as thick; propodus in the former 7,27-, 

 in the latter 7,46-times as long as broad in the middle, armed in the former with 8, in the 

 latter with 7 spines; propodus in the former 1,55-, in the latter 1,51-times as long as the carpus ; 

 dactylus in the former measuring just one-third of the propodus, in the Lucipara-specimen it is 

 a little shorter, measuring rr of the propodus and the accessory claw or tooth, at one-fourth 

 of its length from the tip, appears in the latter somewhat smaller than in the type. 



The legs of the 4 th pair that are missing in the Red Sea specimen, agree with those 

 of the 3 ld , the merus appears, however, 5,3-times as long as wide in the middle. 



Remarks. A. aglaopheniae Borr. from the Engineer Group, British New Guinea 

 (A. Willey's Zoolog. Results, Part IV, 1899, p. 417, Fig. 13^1 — 13/), is apparently one of the 

 most closely related species. It differs, however, by the orbital hoods being acute in front, but 

 bearing no spines, by the shorter stylocerite, by the upper margin of the merus of the laro-e 

 cheliped terminating in a slender spine and probably by more other characters. 



General distribution: Red Sea (Heller); Mahé (Coutière). 



7. Alpheus ventrostis H. M.-Edw. 



H. Milne-Edwards, Hist. Nat. Crust. II, 1837, p. 352. 



H. Coutière, Alpheidae Mald. and Laccad. Archip. 1905, p. 882. 



Syn.: Alpheus laevis Randall, Journ. Acad. Nat. Sc. Philadelphia, 1839, p. 141 ; J. D. Dana, 1. c. 

 1852, p. 556, PI. 35, Fig. 8; C. Spence Bate, Report Challenger Macrura, 188S, p. 555, 

 PI. XCIX, Fig. 3; J. G. de Man, Abhandl. Senckenb. Naturf. Gesells. XXV, 1902, p. 861. 



Stat. 78. June 10 11. Lumu-Lumu-shoal, Borneo-bank. Reef. 10 specimens, 5 of which are 



207 



egg-bearing. 



