218 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.21 



Atlantic analogue: Sphenocarcinus corrosus A. Milne Edwards. 



Diagnosis: Carapace unevenly tuberculate, lateral margins conspicu- 

 ously quadridentate. Rostral horns contiguous, length of rostrum not 

 exceeding postrostral portion of carapace. A blunt preorbital tooth. Cheli- 

 peds not appreciably more massive than walking legs. Male first pleopod 

 with a blunt heel, a large opening, and a thickened but pointed tip. 



Description : Surface of the body and limbs clothed with a short, close 

 pubescence. Rostral horns long, horizontal, and terminating in blunt 

 points. A more or less broken, longitudinal, rounded ridge running along 

 the median line of the carapace, from the base of the rostrum to the 

 intestinal region, rising into a prominent tubercle on the gastric area. 

 A transverse flattened tubercle on the cardiac region, and two roundish 

 ones on each branchial region. Anterolateral margin of the carapace 

 armed with four prominent tubercles or large teeth, counting the one at 

 the external orbital angle ; these teeth increasing in size successively from 

 the first to the last one. Upper margin of the orbit thickened and pro- 

 duced into a blunt preocular tooth. Outer margin of the pterygostomian 

 region furnished with two or three rounded tubercles. 



Merus of the chelipeds with two short spines at the proximal end on 

 the superior border and one at the distal extremity ; otherwise the limbs 

 unarmed ; the fingers of the chela short, gaping slightly at the base, and 

 with blunt tips; no teeth on cutting edges. (Faxon, modified) 



Material examined: 10 specimens from 5 stations. (See Table 42) 

 From Puerto Refugio, Angel de la Guarda Island, to Boca de la Trini- 

 dad, Gulf of California, Mexico ; off Nuez Island, Cocos Island, Costa 

 Rica; and off Medidor Island, Bahia Honda, Panama. In addition to 

 the above, 5 specimens from 2 Galapagos Islands stations (Garth, 1946, 

 p. 379). 



Measurements: Largest specimen, a male: length 30.0 mm, width 

 20.0 mm, rostrum 14.0 mm, basal width 4.0 mm, cheliped 23.7 mm, 

 chela 10.6 mm, dactyl 4.5 mm, ambulatory legs 37, 24.7, 21.5, and 19.5 

 mm, respectively. Ovigerous female: length 23.1 mm, width 16.7 mm, 

 rostrum 7.7 mm, first ambulatory leg 27.6 mm. 



Color in life: Olive brown, usually darkest posteriorly. In the adult 

 males the entire cheliped was bright rose red, sometimes speckled with 

 black, while the projecting parts of the ventral surface were similarly 

 colored. Large females occasionally also had a tinge of pink ventrally. 

 Eggs bright scarlet or grenadine orange to mulberry red. (Crane) See 

 also Garth (1946, p. 379). 



