62 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 24 



Ecology: Commonly found in the littoral under stones; rarely from 

 coral in shallow water. Lockington reported it from 5 fathoms; the 

 I'clcro III dredged it once in 10 fathoms from a sand and rock bottom, 

 and once in 22 fathoms from a coral rock bottom. 



Ovigerous females were taken in January, February, and March. 

 Out of a total of 119 female specimens, only 14 were egg-bearing. 



Relationships : The only species to which Petrolisthes hirtipes is at 

 all closely related is P. nigrungiiiculatus Glassell, which occupies ap- 

 proximately the same range. 



Remarks: Of the extant syntype in the Paris Museum, here desig- 

 nated lectotype, Mr. J. Forest writes as follows: "Les pieces buccales 

 du cote droit et plusieurs pattes ambulatoires manquent." 



A. Milne Edwards and Rouvier (1894, p. 293, footnote) referred 

 to Petrolisthes hispidiis, apparently a lapsus for P. hirtipes. The ab- 

 sence of mouthparts on the right-hand side as noted by Forest in the 

 preceding paragraph may be accounted for by the fact that those au- 

 thors used the type specimen in a study of the structure of "le fouet 

 exopodial des maxillipedes anterieurs" of various porcellanids (see A. 

 Milne Edwards and Bouvier, 1894, footnote, pp. 292-293). 



Range: Bahia de la Magdalena, Baja California; entire Gulf of 

 California, from Bahia Cholla south to Cabo San Lucas. 



Petrolisthes nigrunguiculatus Glassell 

 Plate 24, fig. 1 

 Petrolisthes nigrunguieulatus Glassell, 1936, p. 282 (type locality, Isla 

 Santa Catalina, Gulf of California) ; 1938a, p. 443. Steinbeck 

 and Ricketts, 1941, p. 457, pi. 29, fig. 5. 



Previous records: Gulf of California. Bahia San Francisquito ; 

 Bahia de San Carlos; Puerto Escondido: J. Steinbeck and E. F. 

 Ricketts (Steinbeck and Ricketts). Isla Santa Catalina: S. A. Glassell 

 (Glassell 1936). Bahia Amortajada; Punta Lobos, Isla Espiritu Santo: 

 J. Steinbeck and E. F. Ricketts (Steinbeck and Ricketts). 



Diagnosis: Carapace nearly smooth; no epibranchial spine; front 

 trilobate; carpus about twice as long as wide, proximal half or two- 

 thirds of anterior margin with about four low, well-separated, roughly 

 granulate lobes; manus with a thick fringe of hair on outer margin; 

 fingers markedly dissimilar in the two chelipeds; merus of walking 

 legs unarmed. 



