of the West Coast of North America. 403 



Front entire, rounded, very slightly projecting in the centre ; 

 postorbital tooth acute. 



Eyes prominent, peduncle short. 



Chelipeds short and stout ; meros with a crista or large tooth 

 at its anterior distal end 5 carpus but little longer than wide, 

 upper surface laminate anteriorly, the thin portion with three 

 teeth, the proximal largest, teeth crenulate along their edges ; 

 upper surface of carpus, as well as the large teeth or crests, 

 beset with granules. 



Hands dissimilar, sometimes the right, sometimes the left 

 being the larger. Palm of larger hand as broad as long, 

 thick, covered with smooth circular tubercles ; poUex stout, 

 short, curved ; dactylus almost cylindrical, punctate, longer 

 than the pollex ; fingers gaping widely, but crossing at 

 the tip. 



Smaller hand with the fingers parallel and in contact 

 throughout. 



Anterior surface of carpus and manus of both chelipeds 

 beset with hairs, longest on the margin. 



Ambulatory feet fringed with scattered long hairs. 



Length of carapax 9 millims., width 9. 



Colour (in alcohol) bright red, deeper on the chelipeds. 



Mulege Bay, San-Jos^ Island; both in the Gulf of Cali- 

 fornia. 



The dactylus in the larger hand is inclined at an angle of 

 about 40° with the anterior margin of the palm. 



The specimens were taken in August or September; and 

 the females are loaded with ova. 



The tubercles of the hand increase to teeth 011 the outer 

 margin, which is thus serrated. 



Petrolisthes [Ptsosoma) biocellatus^ nov. sp. 



Carapax orbicular, convex, regions indistinct ; front entire, 

 almost straight, postorbital spine acute. 



Chelipeds short, stout, equal ; meros laminate at its distal 

 anterior end ; carpus as broad as long, the upper anterior por- 

 tion produced forwards as a thick lamina, divided into three 

 low lobes ; manus stout, the palmar portion about equal in 

 length to the carpus. 



Surface of carapax and chelipeds smooth and shining, with- 

 out hairs or set^e ; carpus and meros of chelipeds somewhat 

 squaraose when viewed with a lens. 



Ambulatory feet beset with long setffi on their anterior 

 surface. 



Colour (in spirits) bright red, a round white spot on each 

 shoulder; tips of the fingers white. 



