Three New Species of Holostomidae

Abstract

Leidy (1856) and Stiles and Hassall (1894:248) recorded the occurrence of Strigea (Holostomum) cornu Nitzsch, a European species from the intestine of Ardea herodias. At the same time Leidy described another form, Holostomum nitidum, from the intestine of Rana pipiens, which Stafford (1902: 724) maintains is a distome and should not be classed in this group. In 1858, Leidy reported Diplostomulum grande Diesing from Strix nivea and also noted later (1890: 416) Tetracotyle typica Diesing from snails, Lymnaea catascopium and Physa heterostropha. Rettger (1897:224) mentions a larval holostome with some notes on its life history but does not describe or name it. Diplostomzulum parvalum has been described by Stafford (1904: 494) as a new species from fishes of Canada. Cooper (1915:191) reported finding Diplostomulum cuticola (v. Nordm.) encysted in the mesenteries, livers and kidneys of several Canadian fishes and D. volvens v. Nordm in the lens of the eye of Micropterus dolomieu. Hemistomum craterum was described from the muskrat by Barker and Noll (1915: 191.), and according to Stiles and Hassall (1894:248), an unnamed species of this genus was recorded from Didelphis virginiana by C. Curtice. Polycotyle ornata Willemoes-Suhm was taken from Alligator lucius (cited after Ward 1918:410). Faust (1917:62) in his life history studies has thrown much light on the development of holostomes. In this work he described three larval forms, Cercaria ptychocheilus, Cercaria (Tetracotyle) flabelliformis, from snails and Tetra.cotyle pipientis from Rana pipiens. During the autumn of 1919, several loons (Gavia immer) were seen in the vicinity of Stillwater, Oklahoma, which is an unusual occurrence. In October of that year three loons were killed and brought to the laboratory. These birds harbored two species of holostomes, one belonging to the genus Strigea Abildgaard 1790, and the other to Hemistomum Diesing 1850. These forms proved to be new species and