458 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.21 



This large and striking species is the American representative of a 

 genus represented in the Indo-Pacific region by Daldorfia semicircularis 

 (Flipse) and D. horrida (Linnaeus). The latter species occurs as far 

 eastward as Hawaii (Edmondson) and has been reported recently from 

 Japan (Sakai). It is most likely to be confused among Pacific American 

 species with Thyrolambrus glasselli Garth ( = T. erosus Rathbun), 

 from which it may be distinguished by the ham-shaped merus of the 

 cheliped, the cristate chelae, the presence of a sternal pit in the female, 

 the denticulate anterolateral margins, and the "eyed" margins of the 

 ambulatory legs. 



Genus SOLENOLAMBRUS Stimpson 



Solenolambrus Stimpson, 1871b, p. 132. Rathbun, 1925, p. 534. 



Pisolambrus A. Milne Edwards, 1878, p. 157 ; type: P. nitidus A. Milne 

 Edwards, 1878 = Solenolambrus tenellus Stimpson, 1871, by mon- 

 otypy. 

 Type species: The Atlantic Solenolambrus typicus Stimpson, 1871, 



type of Solenolambrus Stimpson by original indication. 



Description: Carapace pentagonal, and more or less broader than 

 long. Posterior side of the pentagon much the shortest, the other four 

 sides about equal. Margin acute on all sides, forming a slight crest. 

 Upper surface naked, glossy, strongly convex, and bearing four pro- 

 tuberances, one gastric, one cardiac, and two branchial. Gastric and 

 cardiac protuberances more or less triangularly pyramidal, and bran- 

 chial protuberance armed with an acute ridge, running obliquely to the 

 posterolateral margin of the carapace. Frontal region slightly convex, 

 and no protuberance on the orbital region. Rostrum short and blunt, or 

 faintly tridentate. Orbits round, with the upper margins entire and 

 smooth. Basal [article] of the external antennae about as long as the 

 next [article]. . . . Epistome concave. From the anteroexternal angle 

 of the buccal area a sharp, elevated, crenulated ridge extending to the 

 outer base of the cheliped, separating the pterygostomian from the sub- 

 hepatic region, the latter also concave and channel-like. When retracted, 

 the extremity of the hand of the cheliped covering the pterygostomian 

 region, forming the afferent passage. External maxillipeds fitting ac- 

 curately the buccal area, and closely against each other within, and the 

 exognath concave, forming part of the wall of the afferent channel, this 

 channel defined within by a slight, elevated ridge on the outer side of the 

 ischium of the endognath ; merus with a prominent anteroexternal angle, 



