CALIFORNIA STALK-EYED CRUSTACEA. 189 



heterochelis with the larger hand lost. The two species 

 may, however, readily be distinguished aside from the 

 great differences in the larger chelipeds, as heferochelis 

 has no ocular spines, while in equidactylus the front is 

 "trirostrate, without sulcus between rostrum and ocular 

 spines" (Lockington). I have examined Lockington's 

 type which has now lost both its hands. 



Alpheus (Betaeus) aequalis (Lock.). 



Betceus equimanus LOCKINGTON, Proc. Gal. Acad. Sci., Vol. VII, 1877, p. 43. 

 Alpheus Harfordi KINGSLEY, Bull. U. S. Geol. Sur., Vol. IV, No. 1, 1878, 



p. 198; Bull. Essex Inst., Vol. X, 1878, p. 58; Ibid. Vol. XIV, 1883, 



p. 124, PI. II, tig. 4. 

 Alpheus cequalis KINGSLEY, Bull. U. S. Geol. Sur. Vol. IV, No. 1, 1878, 



p. 199. 

 Betceus cequalis LOCKINGTON, Ann. Nat. Hist. (5), Vol. I, 1878, p. 478. 



Carapace moderately compressed, the dorsal side nearly straight. Front 

 devoid of spines, emargiuate in the middle and rounded in front of the 

 eyes. Basal spine of the antennules long and slender, reaching beyond 

 the middle of the second joint; second joint about twice the length of the 

 third; the inner flagellum may exceed the length of the carapace; outer 

 flagellum much shorter than the inner one, with the slender terminal por- 

 tion subequal to the basal part. Second joint of the antennas with a spine 

 below the articulation of the acicle; peduncle about equaling that of the 

 antennules; scale narrowly oblong, nearly reaching the tip of the peduncle, 

 the outer margin nearly straight and ending in a strong spine which is 

 separated by a deep, narrow cleft from the membranous portion; flagellum 

 shorter than the body. Maxillipeds scarcely reaching the tip of the an- 

 tennal peduncle. Anterior chelipeds subequal; merus trigonous, com- 

 pressed, scarcely more than twice as long as high; carpus devoid of a tooth 

 or spine; hands oval, vertical, smooth, strongly compressed, and devoid 

 of grooves or inequalities; dactyl slender, articulated on the lower side of 

 the hand, and working vertically, the inner margin straight or somewhat 

 concave near the base; pollexmuch wider than the dactyl; the entire inner 

 margin may be straight, or there may be a deep, rounded notch near the 

 base; tips of the fingers curved and crossed when closed; inner margins 

 pubescent, the rest of the hand naked. Carpus of the second pair of legs 

 five- jointed, the first joint about as long as the three following ones com- 

 bined, which are subequal and shorter than the fifth; hand narrow, palm 

 nearly as long as the fingers or the last joint of the carpus. Posterior legs 



