Catalog number(s): USNM 635627 Subject: shell Artist: Ryan, Molly Kelly Medium: Airbrushed acrylic and plastic pencil on Denril drafting film Published: Hershler, R. 1996 Review of the North American aquatic snail genus Probythinella (Rissooidea: Hydrobiidae). Invertebrate Biology 115(2):120-144. Fig. 1F