278 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.21 



In order to preclude similar difficulty with respect to material from 

 Ecuador, the writer has elected to include specimens earlier determined 

 for him by Rathbun as Pelia tumida, in his series of material examined 

 of P. pacifica, which has for its range the Bay of Panama in its broadest 

 sense. The pleopods of the males from La Libertad tend to support this 

 view. Similarly, for zoogeographical reasons, he prefers to consider P. 

 pacifica, rather than P. tumida, the Pacific analogue of the Atlantic P. 

 mutica (Gibbes). 



Genus PISOIDES Milne Edwards and Lucas 



Pisoides Milne Edwards and Lucas, 1843, p. 10. Dana, 1852, p. 79. 

 A. Milne Edwards, 1875, p. 74. Rathbun, 1925, p. 284. 



Type: Pisoides tuberculosus Milne Edwards and Lucas = Hyas 

 edwardsi Bell, by monotypy. 



Description: Carapace much longer than wide, trianguliform, slightly 

 swollen. Gastric and genital regions very apparent and separated from 

 each other, as well as from the branchial regions, by rather deeply marked 

 furrows. Rostrum, directed a little obliquely downward, equal in width 

 to the buccal cavity ; armed with two spines, very elongate and divergent 

 at their extremity. Eyes imperfectly retractile ; orbital cavity almost en- 

 tirely filled by the base of the short, medially constricted ocular peduncle. 

 Orbit presenting a notch on its superior margin and not armed with a 

 tooth above its internal angle, as in Pisa; below, this cavity very incom- 

 plete, but with a small spine near the base of the antenna; finally, the 

 external orbital angle occupied by a large and very sharp tooth. Basal 

 article of the antennae a little longer than wide, and adorned with a 

 small tubercle advancing between the movable flagellum and the orbit; 

 the first movable article, much longer than the preceding, wide, very 

 compressed ; the second article, a little shorter, reaching the extremity of 

 the rostrum or surpassing it. Antennules and mouth parts disposed like 

 those of Pisa. Epistome nearly linear. Sternal plastron as long as wide. 



Chelipeds in both sexes short, composed of rather robust articles, and 

 terminating in slender, elongate, slightly curved fingers finely denticulate 

 on the inner side. Legs diminishing progressively in length from the first 

 pair; first pair much longer than the cheliped; merus and carpus broad 

 and compressed ; propodus cylindrical, the dactylus short, very crescentic, 

 and non-denticulate. 



Abdomen in both sexes composed of seven segments. ( Milne Edwards 

 and Lucas, modified) 



