Introduction^ 



In January, 1823, the corvette Coquille, on a voyage around the world 

 under the sponsorship of the French government, visited the port of Con- 

 cepcion in Chile. During their stay at Concepcion members of the ex- 

 pedition collected specimens on Peninsula de Talcahuano, including a 

 porcellanid crab to vv^hich Guerin (1831) gave the name Porcellana vio- 

 lacea. This was the first porcellanid to be reported from western America. 



The advent of the Coquille marks the beginning of a long history of 

 porcellanid collecting in the eastern Pacific. Since that time many ex- 

 peditions and individual collectors have combed the west American coasts 

 and their outlying island groups, assembling a vast amount of material 

 that has found its way into museums in America and Europe. As a result 

 of studies on portions of this material, a large body of literature on east- 

 ern Pacific porcellanids has accumulated. 



Prior to the present study, however, the porcellanid fauna of the 

 eastern Pacific had not been studied as a unit and was not at all well 

 known. Many species, including some that have since proved to be com- 

 mon, were undescribed. Many existing descriptions were inadequate, and 

 others, while more detailed, lacked illustrations. As a result, specimens 

 (particularly those from areas in which the family had received less at- 

 tention) were often difficult to place, even after a successful search 

 through scattered literature for whatever information might be available. 



This study was prompted by a desire to learn more about the com- 

 position of the eastern Pacific porcellanid fauna and the distribution and 

 interrelationships of the various species. It is intended as a contribution 

 toward a much-needed revision of the family, and may also serve as an 

 aid to ecologists, natural history students, and others who frequently 

 encounter porcellanids among collections from the littoral and sublittoral. 



^This study was supported by a grant from the National Science Foundation. 



1 



