182 CALIFORNIA ACADEMY OF SCIENCES. 



Anterior chelipeds stout, ofteu very unequal. Second pair filiform, carpus 

 cylindrical, auuulated, hands small. 



Type. A. rapax FA BE. 



KEY TO THE SPECIES OF Alpheus. 



Front with a rostrum. 



A spine on the infero-distal angle of the merus of the 



ambulatory legs A. damator. 



No uxeral spine. 



No spine on the second basal antenual joint A. barbara. 



A spine on the basal autenual joint. 

 Front trispinose. 



Fingers of larger hand longitudinal; dactyl 



working nearly vertically A. equidactylus. 



Fingers of large hand not longitudinal; dactyl 



short, curved, working horizontally . . . A . bellimanus. 



Front with but one spine A . calif orniensis. 



Front devoid of a rostrum; dactyl joined to the lower side of 

 ' the hand (Genus Betceus Dana). 



Front emargiuate in the center; hands oval A. cequalis. 



Front not emargiuate in the center; hands long and 



narrow A . longidactylus. 



Alpheus clamator Lock. 



Alpheus clamator LOCKINGTON, Proc. Gal. Acad. Sci., Vol. VII, 1877, p. 43; 



Ann. Nat. Hist. (5), Vol. I, 1878, p. 469. KINGSLEY, Bull. Essex Inst., 



Vol. X, 1878, p. 58; Ibid., Vol. XIV, 1883, p. 117. 

 Alpheus transverso-dactylus KINGSLEY, Bull. U.S. Geol. Sur., Vol. IV. No. 



1, 1878, p. 196; Bull. Essex lust., Vol. X, 1878, p. 58. 

 Alpheus candei KINGSLEY (not GUERIN), Bull. Essex Inst., Vol. XIV, 1883, 



p. 124. 



Front trispinose, the median spine short and separated by a deep sulcus 

 from the small, acute, lateral spines which project nearly as far forward. 

 Antero-lateral angle of the carapace devoid of a spine. Basal spine of the 

 antennules broad, scarcely reaching the extremity of the first joint; second 

 joint about twice as long as the third; outer branch of the flagellum much 

 shorter than the inner one, the slender terminal portion shorter than the 

 basal part; inner flagellum longer than the carapace. Second joint of the 

 antenna with a spine below the articulation of the acicle; acicle narrow, 

 nearly as long as the peduncle, with the outer side concave and ending in 

 a strong spine which is separated by a deep, narrow cleft from the mem- 

 branous inner portion; flagellum longer or shorter than the body. Max- 

 illipeds about equaling the autennal peduncle. Chelipeds very unequal; 



