280 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.21 



Diagnosis: Carapace with tubercles of median and branchial regions 

 obscured by villosity. Rostrum flattened, horns divergent. Basal antennal 

 article subquadrate, a spinulous tubercle at anteroexternal angle and a 

 similar tubercle just outside base; succeeding two articles broadened. 

 A sharp postorbital, but no preorbital spine. A stout spine at distal end 

 of merus of cheliped and walking legs. Male first pleopod broad and 

 flattened nearly to tip, a row of spinules on concave margin. 



Description: [Rostrum] flattened, with the horns evenly and slightly 

 divergent and setigerous within. [Basal article] of the antenna subquad- 

 rate, with the outer angle projecting. [First movable article] fully twice 

 as long as the [second], both flattened and ciliate on the outer side, the 

 [second] being ciliate on both margins. [Anteroexternal] angle of [basal 

 article] set with minute spinules or hairs, a prominence at posterior angle 

 raggedly but minutely denticulate. Branchial regions tumid, with two or 

 three faint tubercles of small size. Cardiac region a broad prominence with 

 a rounded surface, a small tubercle on either side a little posteriorly. 

 [Gastric] region prominent with a low posterior tubercle, another oblong 

 one anteriorly equally distinct. Outer orbital [spine] acute. Intestinal 

 region with a small tubercle, but all tubercles concealed mostly by the 

 villosity of the surface, and seen only on its removal. External maxillipeds 

 pubescent, outer margin of the palpus with a re-entering angle a short 

 distance from its upper extremity. Legs with a fringe of rather short 

 hairs on opposite (upper and lower) margins. (Dana) 



Carapace entirely covered with small rounded pits serving for the 

 insertion of the hairs ; branchial, gastric, and genital regions ornamented 

 with prominent tubercles. Chelipeds having the anterior margin of the 

 merus armed on its upper part with a strong spine ; first pair of walking 

 legs remarkable for their strongly compressed merus, with their superior 

 margin crested ; merus of the following legs broad, flattened, and rounded 

 above ; a very pronounced spine at their external margin, especially in the 

 first pair of legs ; carpus short, broad ; the propodus elongate and cylin- 

 drical. Abdomen in both sexes entirely smooth. (Milne Edwards and 

 Lucas, modified, of Pisoides tuberculosus) For a description of one of the 

 original type specimens of P. tuberculosus in the Museum of the Phila- 

 delphia Academy of Natural Science, see Rathbun (1925, p. 286). 



Material examined: Hancock expeditions material: Five specimens 

 from three stations, all in Peru. Lund University Chile Expedition 

 material: 16 specimens from 11 stations, all in Chile. (See Table 57) 

 From San Nicolas Bay, Peru, to Paso Tenaun, south of Punta Tenaun, 

 island of Chiloe, Chile. 



