28 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 24 



27a. Carapace covered with short transverse piliferous striations 

 and large flattened tubercles; carpus about 2^^ times as 

 long as wide, margins subparallel. . . . rathbunae 



27b. Carapace smooth or granular, never with piliferous striations. 28 



28a. Carapace nearly smooth posteriorly, often granular anteriorly ; 

 front with a deep median groove; carpus a little over twice 

 to nearly 3 times as long as wide ; merus of walking legs with 

 a fringe of hair on anterior margin (California and western 

 Baja California) manimaculis 



28b. Carapace nearly smooth anteriorly as well as posteriorly; 

 median groove of front usually faint ; carpus 2 J^ to 3 times 

 as long as wide; merus of walking legs naked or with traces 

 of hair (Gulf of California). ..... gracilis 



29a. Carapace subquadrate, the lateral margins nearly parallel pos- 

 terior to epibranchial angle ; fingers often short and stubby. 30 



29b. Carapace subovate, the lateral margins not parallel ; fingers not 



short and stubby 31 



30a. Anterior and posterior margins of carpus subparallel, un- 

 armed ; merus of walking leg 3 not inflated. . galapagensis 



30b. Proximal ^ of anterior margin of carpus lobed, distal third 

 subparallel with posterior margin ; merus of walking leg 3 in- 

 flated. tonsorius 



31a. Front triangular, the inner orbital angle not produced. . 32 



31b. Front sinuously triangular to tridentate, the inner orbital 



angle produced 36 



32a. Carpus without a lobe on anterior margin, anterior and pos- 

 terior margins subparallel eriomerus 



32b. Carpus lobed on anterior margin 33 



33a. Carpal lobe occupying proximal J4 of anterior margin, an- 

 terior and posterior margins otherwise subparallel ; merus of 

 walking leg 3 not inflated cabrilloi 



33b. Carpal lobe not confined to proximal J4 of anterior margin, 

 anterior and posterior margins converging distally from its 

 highest point ; merus of leg 3 inflated 34 



