374 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.21 



Description: Carapace naked, depressed, deeply areolate, areolations 

 less broken than in Mithrax sculptus, punctate, a transverse [row] of 

 five tubercles on the gastric region and two more acute ones on the outer 

 posterior portion of each branchial region, two prominent tubercles at 

 the base of the rostrum, one on each side of the median line. Rostrum 

 short, bifid, outer margins of horns arcuate, inner straight. Orbits with 

 one distinct fissure above, inner angle prominent, rounded ; outer also 

 rounded but less prominent ; external hiatus a rounded opening. Antero- 

 lateral margin with three teeth besides the external angle of the orbit, 

 first and second teeth stout, prominent, obtuse, the second the larger; 

 third tooth slender, acute, hooked forward; a small acute tooth on the 

 posterolateral margin behind the lateral angle. A tubercle on the sub- 

 hepatic region beneath the first tooth of the anterolateral margin. An 

 oblique row of rounded tubercles running backward from the palatal 

 region. Basal article of antenna with two short blunt teeth. 



Chelipeds small ; posterior margin of merus four-toothed, upper sur- 

 face with one tooth, inner margin with a single rounded tubercle ; carpus 

 prominently tuberculate; hand smooth, inflated, cristate above at the 

 base, a small depressed tubercle on the outer surface at the articulation 

 with the carpus ; fingers moderately gaping, denticulated at the extrem- 

 ity, a basal tooth on the dactylus in both sexes, but larger in the male. 

 Ambulatory [legs] with spinous tubercles on the basal [articles], becom- 

 ing obsolete on the distal ones; dactyli strongly arcuate. (Kingsley, of 

 Gulf of California specimens sent by Lockington) 



Material examined: 483 specimens from 37 stations. (See Table 77) 

 From Agua Verde Bay, Gulf of California, Mexico, to Manta Bay, 

 Ecuador. Absent from Revilla Gigedo and Galapagos Islands collec- 

 tions. 



Measurements: Male neotype: length 14.3 mm, width including 

 spines 20.2 mm, without spines 16.9 mm, rostrum 0.5 mm, width 2.5 

 mm, cheliped 24.0 mm, chela 12.9 mm, dactyl 7.6 mm, height of 

 palm 6.8 mm, ambulatory legs ca. 19.0, 17.8, 16.5, and 15.0 mm, 

 respectively. Ovigerous female: length 12.5 mm, width including spines 

 16.8 mm, without spines 14.6 mm. 



Color in life: Carapace mottled chocolate brown and dull olive 

 green ; eyes chocolate brown ; chelipeds and legs like carapace ; hairs 

 olive; distal half of chelae flesh pink; sternum and maxillipeds plain 

 olive ; abdomen white with segments brownish ; underside of ambulatories 

 greenish white. (Crane, of Costa Rican specimens) 



