Two New Species of Cotylomicrocercous Cercariae from Indiana

Abstract

The prosobranch gastropod, Goniobasis depygis (Say), is an exceedingly abundant species in certain streams of southern Indiana. Several hundred specimens have been taken from McCormick's Creek during the past two years and examined for trematode parasites. The species found include the cercariae of Proterometra macrostoma (Faust) and Macravestibulum obtusicaudum Mackin, Cercaria vogeli Cable, an unidentified xiphidiocercaria of the Virgula group, and two new species of cotylomicrocercous cercariae for which the names C. trichocephala and C. abbrevistyla are proposed. The snails were isolated in finger bowls and the cercariae that emerged were studied alive, both with and without intra vitam staining, and fixed and stained with paracarmine. All measurements given below were taken from living material under light cover glass pressure, and represent the averages of a number of determinations. All drawings are to scale and, with the exception of Figure 3, were made from numerous observations and measurements of structures represented (except flame cells). Figure 3 was drawn from a living specimen with the aid of a camera lucida.