350 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 21 



Localities subsequently reported, with collectors: Mexico: Lower 

 California: L. Diguet (Bouvier) ; Gulf of California: Tepoca Bay, 

 Fred Baker, California Academy of Sciences Expedition (Rathbun, 

 1924c) : Concencion Bav and Pt. Marcial Reef, Steinbeck and Ricketts 

 (Steinbeck and Ricketts) ; Port [Puerto] Escondido, San Jose Island, 

 and La Paz. W. J. Fisher (Lockington, as Ala spinosa) : Mexico south 

 of Cape Corrientes: Chamela Bay and Sihuateneio, Zaca (Crane) ; 

 Manzanillo, C. R. Orcutt (Rathbun, 1925). Costa Rica: Port Parker, 

 Port [Puerto] Culebra. Piedra Blanca, Jasper Island, Ballenas Bav, and 

 Uvita, Zaca (Crane). Panama: Vettor Pisani (Cano, as Mitrax trigon- 

 ofius) : Bahia Honda, Zaca (Crane) : Pearl [Perlas] Islands, S. W. 

 Garman (Rathbun, 1925). Colombia: Utria Bav [Port Utria], Askoy 

 (Garth). 



Atlantic analogue: None. Confined to the Panamic province. 



Diagnosis: Carapace broader than long; rostrum from one-fourth to 

 one-fifth as long as remainder of carapace. Rostral and antennal spines 

 acute, subequal. Chelipeds crested and tuberculate ; walking legs cristate 

 and dentate. Male first pleopod with apex swollen at base, tip pointed, 

 two triangular lateral flanges. 



Description : Carapace devoid of granulations, but a certain number 

 of projections [i. e., nine or ten gastric] on the gastric, cardiac, and 

 branchial regions. Several hairs, short and arranged in little tufts, cover- 

 ing these projections. Frontal region broad and formed : first, by the two 

 pointed rostral horns, extending parallel to each other, and united at 

 their base; measured from the orbit, about one-fifth the length of the 

 carapace ; second, by the preorbital horns, shorter and situated at a level 

 superior to the preceding. External orbital angle small and dentiform. 

 Lamellate expansion of the lateral margins irregularly scalloped. A first 

 triangular tooth occupying the hepatic region, separated by a deep 

 rounded notch from the lamellate prolongation of the branchial regions; 

 the latter bearing in front a strong flattened tooth, the point bent a little 

 forwards, then several not very deep indentations. Posterior margin sur- 

 mounted by a marginal crest, separated from the lamellate branchial 

 expansion by a notch ; several tufts of hair occurring along this margin. 



Chelipeds slender and a little longer than the first pair of ambulatory 

 legs; arm bearing a toothed crest above, and a spine at its extremity; 

 forearm provided with cristiform projections; hand smooth, except for 

 several very fine granulations ; fingers scarcely gaping, provided with fine 

 denticulations and tapering. Ambulatory legs short ; their first articles 

 having a prismatic triangular shape, the projecting edges being cut into 



