Studies on Monogenetic Trematodes XII. Dactylogyridae from Wisconsin Fishes

Abstract

The 17 species of Monogenea treated herein were collected from Wisconsin waters in 1947 by Dr. R. V. Bangham of Wooster College, Wooster, Ohio, to whom the authors express a debt of gratitude. The host material was first frozen and then preserved in formalin. After arrival at our laboratory, the gills were placed in small vials about twothirds full of tap water and shaken vigorously in order to free the parasites from the branchial tissue. This material was then transferred to Syracuse watch glasses and diluted and decanted until clear enough for reliable exam: ination with a dissectoscope. Individual specimens were collected with a capillary pipette equipped with a rubber bulb and transferred to clear water for removal of excess mucus. Each of the permanent mounts was made by selecting a specimen microscopically with a capillary pipette and transferring it to a drop of solidified glycerin-gelatin medium on a clean glass slide. A cover glass which was placed thereon settled in place as the medium was melted with gentle heat. The slide was cooled, the medium congealed, and a permanent mount was thus produced. Measurements were made with a compound microscope and a calibrated ocular micrometer for (1) body length, (2) greatest body width, (3) length of haptoral bars, (4) length and (5) width of anchors, (6) length of cirrus, (7) length of accessory piece, (8) length of hooks, and (9) t-ransverse diameter of pharynx. Curved structures were measured as a straight line extending between the two most distant parts of such structures. Measurements of anchor lengths, for example, extend from the tip of the superficiat root to the most distant point on the curved portion in the region of junction of the shaft and point. The width of the anchors is the greatest width of an anchor base. A mean measurement was calculated (in the case of two or more specimens) and consists of an average derived from the measurements of the same structure in different individuals. All measurements, except those for body length, and body width which were made with a lowpower objective (16 mm), were done with an oil-immersion objective. Available specimens up to a maximum of 27, were used in the treatment of a given species. One species of Tetraonchinae (Urocleidus chrysops from the white bass, Lepibema chrysops) and seven Dactylogyrinae (Dactylogyrus attenuatus, D. claviformis, and D. lineatus (all) from the northern creek chub, Semotilus a. atromaculatus; D. distinctus from the northern mnimic shiner, Notropis v. volucellus; D. dubius, D. pyriformis, and D. vannus from the northern common shiner, Notropis cornutus frontalis) are new. The host distribution of the remaining nine species is as follows: Cleidodiscus