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 431 693-433—63 1
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