Phagocata gracilis
Year: 2026
Type: other
Abstract: Phagocata gracilis (Haldeman, 1840) (Figures 9–14) Material examined and distribution ZMA V. Pl. 1929.1, Troupe Springs, Washington County, Maryland, U.S.A., November 21 st 1989, sagittal sections on 8 slides; ZMA V. Pl. 1929.2, ibid., sagittal sections on 6 slides; ZMA V. Pl. 1929.3, ibid., sagittal sections on 7 slides; ZMA V. Pl. 1929.4, ibid., sagittal sections on 7 slides; ZMA V. Pl. 1929.5, ibid., sagittal sections on 7 slides; ZMA V. Pl. 1929.6, ibid., sagittal sections on 7 slides; ZMA V. Pl. 1929.7, ibid., sagittal sections on 6 slides; ZMA V. Pl. 1929.8, ibid., sagittal sections on 9 slides; ZMA V. Pl. 1929.9, ibid., sagittal sections on 11 slides; ZMA V. Pl. 1929.10, ibid., horizontal sections on 8 slides; ZMA V. Pl. 1929.11, ibid., transverse sections on 12 slides; ZMA V. Pl. 1241.1, ibid., whole mount on 1 slide; ZMA V. Pl. 1941, ibid., preserved specimen; ZMA V. Pl. 1931.1, Dunkard Lick Spring #1, Garrett County, Maryland, U.S.A., February 2 nd 1989, sagittal sections on 4 slides; ZMA V. Pl. 1931, ibid., preserved specimens. Description The specimens were dark coloured on both the dorsal and the ventral surface and have two or more eyes (Fig. 9) and measured 10–13 mm in length and 2.5–3 mm in width, as measured on preserved specimens. The specimens are polypharyngeal, with one large pharynx and about 40–50 small pharynges. The entire set of pharynges makes up for about half of the total body length (Fig. 10). The specimens have no adhesive organ. The testes are situated ventrally, extending dorsally beyond the midline of the body. The follicles are located from the level of the ovaries to the posterior end of the body. The vasa deferentia run on the ventral side of the body, heading posteriorly.At the level of the penis bulb, the vasa deferentia recurve sharply, heading anteriad. Subsequently, at the anterior part of the penis bulb the vasa deferentia curve laterally and enter the ventro-lateral wall of the penis bulb. Within the bulb, they run besides each other and open into a small seminal vesicle. Characteristically, this small seminal vesicle appears to have no direct connection with the penis lumen (Figs 11–14), which communicates with the ejaculatory duct. Seminal vesicles, penis lumen and the ejaculatory duct have a folded epithelium. The ejaculatory duct opens at the tip of the penis papilla. The penis papilla is conical or finger-shaped, extending far into the male or common atrium and being provided with a small, pointed tip; it is covered with a nucleated epithelium, which is underlain with a thin layer of intermingled circular and longitudinal muscle fibres. The male atrium is surrounded by an inner layer of circular muscles and an outer layer of longitudinal muscles. In one specimen (ZMA V.Pl. 1929.4; Fig. 12), the male atrium appears to have an intermingled layer of circular and longitudinal muscles. The ovaries are situated directly posterior to the brain. The rather large testes are basically situated ventrally but may extend dorsally to well beyond the midline of the body. The testes extend from directly posterior to the ovaries into the posterior end of the body. The copulatory bursa is situated directly behind one of the pharynges in the dorsal part of the body. It is connected to the common atrium by a long, narrow bursal canal, which runs in the dorsal part of the body. The nucleated bursal canal is surrounded by a weak coat of muscles that exists of intermingled circular and longitudinal muscles, while near the copulatory bursa it is made up of predominantly circular muscles. Near the common atrium, the bursal canal becomes wider, and therefore may be called a vagina. This vagina opens from the dorso-posterior side into the common atrium. The oviducts fuse to form a common oviduct. Shell glands discharge through the epithelium of the proximal, dorsal section of the common oviduct, and also through the distal ends of each of the two oviducts. The common oviduct opens into the posterior part of the male atrium, from the dorsal side. Female and common atrium are surrounded by a coat of intermingled circular and longitudinal muscles.
Language: English
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7225099182