CALIFORNIA STALK-EYED CRUSTACEA. 159 



marginal spine beneath the lateral teeth of the front 

 was absent, although they agreed with specimens from 

 northern California in every other essential feature. 



Genus Callianassa Leach. 



Rostrum absent or reduced to a small point. Eye-peduncles flattened; 

 cornea median, small or absent. Antennular flagella never shorter than 

 the preceding joint. No antennal scale. External maxillipeds operculi- 

 form. First pair of pereopods very unequal and furnished with well- 

 developed chelae; second pair small and chelate; third pair with the 

 penultimate joint broadly expanded; fifth pair subchelate. Second pair 

 of abdominal appendages in the female slender, the succeeding ones 

 broad, foliaceous, and fringed with ciliated hairs. Caudal appendages 

 wide. Gills with flattened filaments. 



In this genus, according to Bate, only arthrobranchiae 

 are present, with the exception of a rudimentary masti- 

 gobranchia on the third maxilliped. 



Callianassa californiensis Dana. 



Callianassa californiensis DANA, Proc. Acad. Nat. Sci. Phila., 1854, p. 175. 



STIMPSON, Journ. Bost. Soc. Nat. Hist., Vol. VI, 1857, p. 489, PI. 



XXI, fig. 4. A. MILNE-EDWARDS, Nouv. Archiv. Hist. Nat. Paris, 



Tome VI, 1870, p. 82. LOCKINGTON, Ann. Nat. Hist. (5), Vol. II, 1878, 



p. 301. 

 Callianassa occidenialis STIMPSON, Proc. Cal. Acad. Sci., Vol. I, 1856, p. 88. 



Front very short and rounded, with a small, triangular tooth on either 

 side between the bases of the ocular peduncles and the antennae. Ocular 

 peduncles subtriangular, approximated at the bases, but diverging towards 

 the acute tips which are somewhat upturned. Antennulary flagella sub- 

 equal. Antennae from one-half to two-thirds the length of the body, the 

 peduncle nearly equalling that of the antennules. Chelipeds in the adult 

 male with one arm enormously developed; ischium of the larger cheliped 

 slender, compressed, incurved, distally widened, and finely denticulated 

 on the acute lower margin; merus about as long as the ischium (generally 

 a trifle longer) but stout, curved, smooth, almost naked except on the cili- 

 ated margins, and furnished with a prominent lobe at its infero-proximal 

 angle; carpus very wide, a little longer than the merus, the outer surface 

 smooth, naked, glossy, and evenly convex as if forming a part of the sur- 

 face of a cylinder; margins acute, ciliated, and minutely serrulated; upper 



