177 



Key to the indopacific species of the genus Alpheopsis Cout. 



rtj Carpus of second legs triarticulate. No extra-corneal spines. Ptery- 

 gostomian angle terminating in an acute triangular point. Legs of 



first pair unknown idiocarptis Cout. 



(H. COUTIERE, in: Bull. Soc. Philom. Paris, 1908, p. 4). 

 a„ Carpus of second legs five-articulate. 



b^ Dactyli of three posterior legs biunguiculate. No extra-corneal spines. 



Legs of the first pair unknown fissipes Cout. 



(H. COUTIERE, in: Bull. Soc. Philom. Paris, 1908, p. 3). 

 b„ Dactyli of three posterior legs simple. 



c. Posterior margin of the telson straisjht or a little convex. 

 d-^ Chelae of first pair entire and smooth. 

 e^ Front without extra-corneal spines. 



f^ Pterygostomian angle of the carapace rounded. 



g^ Rostrum acute aequalis Cout. 



(H. COUTIERE, in: Bull. Mus. Paris, 1896, N" 8, p. 380). 



g„ Rostrum truncate aequalis Cout., var. truncatus Cout. 



(H. COUTIERE, Alph. Maid, and Lace. Archip. 1905, p. 868, Fig. 139). 



/j Pterygostomian angle terminating in a small acute tooth. 

 Rostrum acute. Antennular peduncle with the second article 

 a little wider than long. Chelipeds unequal, palm of the 



large chela one-fourth longer than the fingers .... consobrinus de Man 

 ^2 Front trispinose. Pterygostomian angle with a small, acute 

 tooth or spine. Chelae of the first jaair in the female with 

 the palm slightly shorter than the fingers. Three posterior 



legs slender, merus of third pair 8-times as long as wide . Chalciope de Man 

 rtf„ Chelae of first pair more or less grooved, with the dactylus 

 lunulate. Front trispinose. 

 e^ Chelae of first pair entirely inverted, equal, dactylus quite 

 inferior. No transverse groove behind the articulation of the 

 dactylus ; cutting-edge of the dactylus with a slight promi- 

 nence, fitting, as in the genus Aniphibetaetis^ into a deep 



groove of the immobile finger Sibogae de Man 



^2 Chelae of first pair unequal, dactylus at most in a horizontal 

 plane. A deep transverse groove behind the articulation of 

 the dactylus, the dactylus with one tooth, the immobile 



finger with two trispinostis Stimps. 



(W. Stimpson, in: Proc. Acad. Nat. Scienc. Philadelphia, i860, p. 32). 



fj Telson terminating, like in the genus Parabetaeus^ in a large, acute 

 tooth, that measures one-ninth the whole length of the telson. No 

 extra-corneal teeth. Rostrum acute. Legs of the first pair unknown. Enryone de Man 



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