276 



Carapace quadrangular or transversely-elliptical, smooth or gra- 

 nulate and pubescent. Palp of external maxillipeds small, with 

 the joints placed end to end, ischium much stronger than merus. 6 



6. Carapace quadrangular, about as broad as long, granulate and 



pubescent, with two tomentose and longitudinal branchio-cardiac 

 grooves. Front bilobed. Walking legs much longer than breadth 

 of carapace; meropodites sharply crenulate throughout; dactyli 



long, those of last pair curved backward Chasmocarcinops Alcock 



Carapace quadrangular or transversely-elliptical, for the greater 

 part smooth and shining, regions little or not defined. Walking 

 legs short, not exceeding breadth of carapace ; meropodites not 

 sharply crenulate throughout ; dactyli very short, sometimes 

 nearly invisible 7 



7. Carapace quadrangular, with some isolated patches of a short 



pubescence. Front triangular. Ischium of external ma.xillipeds 

 widening towards merus, broadest at anterior margin and with 

 the antero-internal angle sharp and freely projecting, merus 

 small, subcircular, with palp inserted at middle of the convex 



anterior margin Voeltzkowia Lenz 



Carapace transverse, especially so in the 9 , lateral margins regu- 

 larly curved, sharp and entire. Anterior margin of front straight. 

 Merus of e.Kternal maxillipeds quadrangular, little narrower, 

 but much shorter than ischium, with palp inserted near antero- 

 external angle of the concave anterior margin. Walking lesfs 

 short; posterior margin of meropodite with some small teeth; 

 dactyli extremely minute, scarcely visible Aphanodactylus n. g. 



Asthenognathus Stimpson. 



1858. Asthenognathus Stimpson. Proc. Ac. So. Philadelphia, 1S58, p. 107. 



This genus contains two species. 

 Key to the species: 

 Posterior margin of carapace 1.5 times as long as fronto-orbital distance. 



Species from Japan A. itiaequipes Stimpson 



Posterior margin of carapace equal to fronto-orbital distance. Species 



from the Gulf of Siam A. hexagotium Rathbun. 



I . Asthenognathus maequipes Stimpson. 



1858. Asthenognathus inaequipes Stimpson. L. c, p. 107. 



1907. Asthenognathus inaequipes de Man. Transact. Linn. Soc.^ London (2), v. 9, p. 392, 



pi. 31, f. 4—6. 

 1907. Asthenognathus inaequipes Stimpson. Smithson. Inst., Miscell. Coll., v. 49, p. 140, pi. 14, f. i. 



12S 



