398 Mr. W. N. Lockington on the Porcellanidea 



pointed and slightly bent ; pollex of right cheliped with an 

 obtuse tip, that of left sharp and slightly bent inwards. 



Upper surface of manus, carpus, and meros covered with 

 tubercles; two distinct longitudinal series of tubercles on each 

 dactyl ns ; the inner margin of the left dactylus, outer margin 

 of both propodi, and inner margin of carpus clothed with a 

 fringe of long setse. 



Ambulatory limbs tomentose above, with a long fringe of 

 setai on both margins ; upper surface granular. 



Length of carapax 7 millims., width 6. 



Dredged in five fathoms, Mulege Bay, Gulf of California ; 

 also at Port Escondido. Several specimens. 



The tubercles of the chelipeds are tipped with red (in 

 spirits) ; and the bent tip of the left dactylus is bright red. 



When the tomentosity of the carapax is rubbed off, the 

 channel between the orbital and antero-lateral margins and the 

 postgastric sulcus are distinct. 



The long setge which fringe the limbs are themselves regu- 

 larly fringed along both sides with shorter sette, appearing 

 like a row of feathers, each with its shaft and pinnules. 



Petrolisthes crenulatus^ nov. sp. 



Carapax covered Avith short plications, becoming rug£e 

 toward the front and antero-lateral margins ; gastric region 

 elevated considerably above the frontal and orbital, the antero- 

 lateral raaro-in continuous, with fom- lobes, Avhich bound the 



• • 1 



gastric region anteriorly. 



Front deflected, consisting of the obtuse preorbital lobes 

 and an obtuse-angled central lobe projecting slightly beyond 

 them ; postorbital tooth slightly marked, not spinous. 



Cardiac region well deiined by longitudinal sulci ; two 

 transverse sulci traceable across the entire carapax, the ante- 

 rior enclosing the gastric region. 



Chelipeds long and flattened. Meros with a blunt tooth at 

 its anterior distal angle ; carpus more than twice as long as 

 wide, w^ith four blunt teeth on its anterior margin, the two 

 central largest ; manus without spines ; fingers of right and 

 left chelipeds differing slightly, those of the right slightly 

 gaping, and the right pollex with a blunt tooth. 



Carpus and manus squamoso-granular, becoming granular 

 on the manus ; the upper surface of both joints tomentose 

 toward the outer margin, especially near the elbow. 



Ambulatory feet smooth, margined with long hairs ante- 

 riorly. 



Length of carapax 10 millims., width 10. 



Port Escondido, Gulf of California. A single specimen. 



