Catalog number(s): USNM 1071402 Subject: shell Artist: Ryan, Molly Kelly Medium: Computer: Adobe Photoshop Published: Hershler, R., Liu, H.-P., Lang, B. 2007. Genetic and morphologic variation of the Pecos assiminea, an endangered mollusk of the Rio Grande region, United States and Mexico. Hydrobiologia, 579, 317-335. Fig. 6