2 U.S. NATIONAL MUSEUM BULLETIN 292 



figures or more complete species bibliographies. Misidentifications, 

 except when they have become firmly established in the literature, 

 are not hsted, and the vahdity of the synonyms usually has not been 

 verified by the examination of type-material. 



We should emphasize that the keys and diagnoses apply only to the 

 species covered by the study and often only to adult males; the identi- 

 fication of female and immature specimens of some species is frequently 

 impossible by current criteria, except by their association with adult 

 males or by similarities in color patterns. The itahcized portions of the 

 diagnoses denote those characters that are unique among the species 

 covered oj eachjamily. 



Most of the Dominican shrimps (Macrobrachium , Atya, and Poti- 

 mirim) occur in two "color phases," one in which yellow, tan, and 

 browTi predominate and the other characterized by blue, gray, and 

 black. Usually only one of the two is described in detail in the color 

 notes presented here. The vivid colors that are displayed, almost 

 wdthout exception, by recently molted individuals become somewhat 

 duU or obscured as the surface of the exoskeleton is scarred, collects 

 silt, or serves as a substrate for the growth of bacteria, algae, and 

 protozoans. Our color notes were recorded from animals that had not 

 become encrusted ^\'ith foreign matter. Because of the variabihty in 

 the actual colors from one individual to another, color charts were not 

 used. Seldom do two specimens have precisely the same color, and 

 occasionally, as in Uca, there is Httle similarity in details of color 

 pattern. Although the descriptions and illustrations of the color pat- 

 terns should facihtate the field identification of the species that occur 

 on Dominica, we trust that collectors will soon learn to recognize the 

 relatively constant aspects of the patterns of each species and to use 

 caution in assigning taxonomic importance to differences that may be 

 due to factors such as immaturity, sex, light adaptation, and extra- 

 neous growth, as well as to intrinsic variation in a species. 



The distributions cited indicate overall ranges and, in parentheses, 

 the West Indian records. As mentioned below, the island records, 

 especially of widely ranging species that have marine larvae, may be 

 indicative only of the diversity of collecting activities. Our search for 

 island records has not been exhaustive, but a number of new ones 

 have been added from previously unpubHshed locality records in 

 the Smithsonian collections. 



The nine species hsted below have been recorded, usually only 

 once, from the West Indies, but the records have proved to be, or 

 are beheved to be, based on errors of identification or documentation, 

 and they have therefore been excluded from consideration : 



Camharellus montezumae (De Saiissure, 1857a). Rhoades (1962, p. 72) mis- 

 takenly indicated that this crayfish had been found "on both sides of the Yucatan 

 Channel." 



