Proceedings of 

 the United States 

 National Museum 



SMITHSONIAN INSTITUTION • WASHINGTON, D.C. 



Volume 115 1964 Number 3490 



SHRIMPS OF THE GENUS BETAEUS 

 ON THE PACIFIC COAST OF NORTH AMERICA 

 WITH DESCRIPTIONS OF THREE NEW SPECIES 



By Josephine F. L. Hart 



Introduction 



Shrimps of the genus Betaeus are members of the section Caridea 

 and the family Alpheidae (or Crangonidae in much of the North 

 American literature). Members of this genus are characterized by 

 the lack of a rostrum in the adult and by the inversion of the "hands," 

 with the result that the dactyls are on the lower side. The terms 

 "visored shrimps" and "hooded shrimps" are sometimes used because 

 the carapace projects forward to overhang the eyes. Up to the present 

 time four species have been recognized as occurring in the area from 

 Mexico to Alaska: Betaeus harrimani Rathbun, B. longidactylus 

 Lockington, B. ensenadensis GlasseU, and B. harfordi (Kingsley). 

 However, these species have not been well defined. 



The sole published record of Betaeus harrimani is the original 

 description by M. J. Rathbun (1904) based on a single female taken 

 in southern Alaska. The examination of a series of both males and 

 females from a number of more southerly locations has made it possible 

 to elaborate on this description. Such an elaboration is especially 



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693-433—63 1 



