3o8 



Brevirostris group. 



Lateral (extra-corneal) spines wanting. Larger chela quadrangular, compressed, often with 

 longitudinal ridges, with a transverse groove near the articulation of the dactylus or not ; 

 dactylus of larger chela of the male sometimes "Balaeniceps"-shaped. Merus of third legs 

 usually unarmed. Dactyli of three posterior legs simple, lanceolate. 



Edwardsi group. 



Lateral (extra-corneal) spines wanting, very rarely [A. hoplites) orbital hoods acute. 

 Larger chela usually more or less compressed, with both the upper and the lower margin 

 emaro-inate and with grooves or depressions on the lateral surfaces. Dactylus of smaller chela 

 of the male often ''Balaeniceps"-shaped, rarely also that of the female. Merus of third legs 

 unarmed or dentate. Dactyli of three posterior legs simple, very rarely [A. hoplites, A. Polyxd) 

 biunguiculate. 



Key to the indopacific species and varieties of the genus Alphetts Y2^ir 



Megacheles group. 



«j Merus of 3'*^ legs unarmed. 



b^ Dactylus of 3"''^ and following legs simple. 



fj Merus of 3'''^ legs 5-times longer than wide. Fingers of the smaller 

 chela slightly shorter than the palm, which is 2,43-times as long- 

 as high staphylinus Cout. 



(H. COUTIERE, in: Bull. Soc. Philom. Paris, 1908, p. 14). 



c„_ Merus of 3'"'^ legs 9, 5-times longer than wide. Inner margin of 

 the merus of the larger cheliped with 4 — 6 small spinules 

 posterior to the spine at distal extremity. Fourth article of carpus 

 of 2°<^ legs usually as long as the 2°'^ and as long as the 5^'^ 

 Fingers of the smaller chela slightly longer than the palm. 

 Larger chela in the male 2,58-times, in the female 2,76-times 

 as lono- as hio-h Hailstonei Cout. var. assivndans de INIan 



c^ Merus of 3'^'^ legs 11 -times longer than wide ^). Inner margin of 

 the merus of the larger cheliped unarmed posterior to the spine 

 at distal extremity. Fourth article of carpus of 2^^ legs as long 

 as the 2°"^ and as long as the 5'^^. Fingers of smaller chela 

 slightly shorter than the palm. Larger chela 3,33-times as long 



as hio-h Hailstonei Cout. 



(H. COUTIERE, Alpheidae Maid, and Laccad. Archip. 1905, p. 879, PI. LXXIV, fig. 18). 



i) This propoition is deduced from the figure. 



176 



