</a> Courtesy Smithsonian Institution National Numismatic Collection. Rare Currency at The Smithsonian The previous coin's older brother the 1849, Gold Rush era double eagle gold coin is valued by collectors the world over. It was the United States of America's first $20 denominational gold coin. Courtesy Smithsonian Institution National Numismatic Collection.
subspecies - (biology) a taxonomic group that is a division of a species; usually arises as a consequence of geographical isolation within a species. race. biological science, biology - the science that studies living organisms. taxon, taxonomic category, taxonomic group - animal or plant group having natural relations.
n. pl. species. 1. Biology A group of closely related organisms that are very similar to each other and are usually capable of interbreeding and producing fertile offspring.The species is the fundamental category of taxonomic classification, ranking below a genus or subgenus. group of organisms having many characteristics in common and ranking below a genus. Organisms that reproduce sexually and belong to the same species interbreed and produce fertile offspring. See Table at taxonomy.