M7 



A. Dactyli of three posterior legs distinctly biunguiculate, the ventral 

 accessory hook making a distinct angle with the posterior margin. 

 Supra-corneal spines wanting. 

 Cj Infra-corneal spine very short. Legs of the first pair of the female 

 as in At li. Xaifaroensis. Dactyli of three posterior legs with the 

 accessory hook conical, much shorter than the principal hook. Granti Cout. 

 (H. Coutière, in: Buil. Soc. Philom. Paris, 1908, p. 2). 



c s Infra-corneal spine hardly shorter than the extra-corneal. Chela of 

 the first pair of the female almost as long, hardly longer than 

 the merus, carpus 2,5-times as long as thick. Dactyli of three 

 posterior legs with the accessory hook slender, a little more 



than half as long as the principal hook parvus de Man 



a 2 Legs of the first pair with the carpi and the chelae directed backward, 

 fitting in the elongate, excavate merus. {Dimorphus group). 

 ó 1 Dactyli of three posterior legs simple. 

 Cj Supra-corneal teeth vvanting. 



d x Carpus of the first pair of legs of the female slender, much 

 longer than the chela. 

 e 1 Rostrum reaching until to the second antennular article . . dimorphus Ortm. 

 (A. ORTMANN, in: Jenaische Denkschriften VIII, 1894, p. 12, Taf. I, Fig. 1). 



e„ Rostrum a little longer than the antennular peduncle . 



dimorphus Ortm. var. monoceros Heller 



(Alpheus monoceros Q. Heller, in : Sitzungsber. Kais. Akad. Wiss. Bd. XLIV, Wien, 

 1861, p. 274). 



d 2 Carpus of the first pair of legs of the female shorter than 



the chela. 



e x Carpus conical, half as long as the merus ; chela slightly longer 



than the merus Minikoensis Cout. 



e z Carpus slender, in proportion to the chela as 0,85 : 1 



Hasioelli Cout. orientalis Pearson ] ) 



(H. Coutière, in: Buil. Soc. Philom. Paris, 1908, p. 2 and J. Pearson, On the 

 Macrura, in: Herdman's Report on the Pearl Oyster Fisheries, 1905, p. 88, 

 PI. II, Fig. 10). 



c„ Supra-corneal spines distinctly developed. 



Legs of the first pair in the female very unequal .... Djiboutensis Cout. 

 (H. COUTIÈRE, Alpheidae Mald. and Lacc. Archip. 1905, p. S56, Fig. 129). 



ö„ Dactyli of three posterior legs biunguiculate. 

 Supra-corneal spines wanting. 



1) The brief description of Ath. Haswelti makes it impossible to indicate a differential character between this species and 

 Ath. orientalis. According to Pearson's figure the proportion between the carpus and the chela should be in this species also 0,85. 



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