ON MOLLUSCA OF THE WEST COAST OP NORTH AMERICA. 351 



chances of error. We shall then know, and not satisfactorily till then, where 

 and how the two great faunas of West N. America, both of which go loosely 

 by the name of " Californian," find their separation. 



The imperfect data of the Pacific coast of Lower California only furnish 

 us with Palliobranchs, I; Lamellibranchs, 60; ordinary Gasteropods, 49; 

 Toxifera, 7; Proboscidifera, 20: total 137 species. As the localities are so 

 far from being satisfactorily established, an exact analysis of them will not 

 here be attempted : but the fauna of each spot will be given entire so far as 

 known, both on the Pacific shores and in the Gulf. The species marked * 

 belong to the Californian type ; those marked f to the Panamic. 



The following list contains the known shells of San Diego : — 



Pholadidea ovoidea. 



Pecten floridus. 



* penita. 



purpuratus. 



' *Parapholas Californica. 



fOstrea conchaphila. 



Saxicava Pholadis. 



f plumula. 



*Petricola Californica. 



Hinnites giganteus. 



*Saxidomus Nuttalli. 



*Helix tudiculata. 



*Platyodon cancellatus. 



* Kellettii. 



*Sphaenia Californica. 



Bulimus pallidior. 



*Lyonsia Californica. 



fMelampus olivaceus. 



Periploma argentaria. 



Haminea vesicula. 



*Solecurtus subteres. 



*Bulla nebulosa. 



* Californianus. 



virescens. 



Sanguinolaria Nuttalli. 



longinqua. 



Psammobia Pacifica. 



Tornatina inculta. 



*Tellina nasuta. 



Mopalia Blainvillei. 



* secta. 



*Acmsea patina. 



pura. 



* persona. 



■ vicina. 



* grandjs. 



Cumingia Californica. 



* spectrum. 



*Semele decisa. 



* scabra. 



flavescens. 



fascicularis. 



* rubrolineata. 



*Fissurella volcano. 



*Donax Californicus. 



*Haliotis Californiensis. 



* Venus Nuttalli. 



* Cracherodii. 



* Californiana. 



* splendens. 



excavata. 



*Osilinus ater. 



dispar. 



*Trochus filosus. 



fluctifraga. 



*Omphalius aureotinctus. 



*Tapes straminea. 



* brunneus. 



*Trigona crassatelloides. 



*Phasianella compta. 



*Cardium Nuttalli. 



fTurbo Fokkesii. 



* Californiense. 



fPetaloconchus macrophragma. 



* substriatum. 



*Cerithidea sacrata. 



t datum. 



albonodosa. 



luteolabrum. 



pullata. 



Cypricardia Californica. 



fNatica uber. 



*Chama exogyra. 



Ranella triquetra. 



■ pellucida. 



muriciformis. 



*Diplodonta orbella. 



Californica. 



fLucina punctata. 



t[01iva splendidula] . 



— -bella. 



Purpura emarginata. 



Californica. 



Columbella carinata. 



Nuttalli. 



Californica. 



fLithophagus attenuatus. 



fNassa luteostoma. 



*Mytilus Californianus. 



fossata. 



Modiola capax. 



f tegula. 



Area pernoides. 



Murex Belcheri. 



*Pecten latiauritus. 





