of the West Coast of North America. 397 



Island, Fisher), and also along the Gulf coast of the same 

 peninsula (Port Escondido ; Las Animas Bay, Fisher) 5 it is 

 found on the islands of the Santa-Barbara group (!Santa-Rosa 

 and San-Miguel Islands, Harford), and thence by Monterey 

 and the Farallones northward at least to Tomales, on the 

 ocean-beach near which place I have procured it in abundance. 

 Probably it extends much further to the northward. 



It is abundant on rocky beaches in some parts 01 San- 

 Francisco Bay. 



Petrolisthes eriomerus, Stimpson. 

 Petrolisthes eriomerus, Stimpson, Ann. Lye. Nat. Hist. N. Y. x. p. 119. 



It is not very unlikely that this may prove to be a variety 

 of P. rupicolus. All the examples of the latter species that I 

 have examined, have the tuft of hair between the fingers 

 below ; in many the posterior or outer edge of the carpus 

 appears denticulated in consequence of the projecting edges of 

 the short rugse, which continue some distance down the outer 

 surface ; and the prominence of the laminate inner lobe varies 

 in different specimens. I have a young Petrolisthes which 

 has a slightly triangular front (projecting much less than that 

 of a somewhat larger P. rupicolus), and the two sides of the 

 carpus parallel. So far it agrees with P. eriomerus ; but the 

 posterior margin of the carpus is not denticulated, and the 

 ambulatory feet are not " everywhere hairy," but covered 

 with granules, except a few hairs on the dactyli. 



I believe this specimen to be the young of P. rupicolus. 



Petrolisthes hirtipes, nov. sp. 



Carapax slightly longer than wide, somewhat pentagonal, 

 a single lobular tooth behind the eye ; upper surface tomen- 

 tose, granular anteriorly. 



Front three-lobed, margined with setae, central lobe low 

 and broad ; no postorbital spine. 



Eyes large and projecting. 



Antennal peduncle armed with tubercles, the largest on the 

 anterior portion of the penultimate joint. 



Meros of chelipeds short, with a long tooth at its anterior 

 distal end ; carpus about twice as long as wide, with two or 

 three teeth on its anterior margin, and a long tooth at its pos- 

 terior distal extremity ; manus flattened, thickest along the 

 centre of its length, and broadest at the insertion of the 

 dactylus ; dactyli dissimilar, that of the left cheliped stout, 

 inserted somewhat obliquely, and very strongly hooked at the 

 tip, which is obtuse and overpasses that of the pollex, that of 

 the right cheliped with the inner edge straight, the tip sharp- 



