Examined specimens 280 to 330 µm long and 75 to 100 µm wide (Figs. 4A, B, 5A). Anterior and posterior ends rounded. Body cylindrical. Epidermis completely ciliated. Many mucoid glands present. Body colorless in transmitted light, but digestive syncytium has brown and slight green coloring. Body-wall musculature with circular muscles that encircle the body along entire length of animal; straight longitudinal muscles present between frontal organ and anterior edge of mouth; longitudinal muscles with a longitudinal orientation anteriorly that bend medially to cross diagonally over the body; longitudinal-cross-over fibers present in dorsal and ventral body walls; longitudinal muscles in the anterior half of the body that wrap around the posterior rim of the mouth (U-shaped muscles) present in ventral body wall (data not shown). Frontal organ well developed. Cell bodies of frontal glands positioned 75µm behind frontal pore (Fig. 4B). Mouth opening on ventral surface, middle of body. Digestive central syncytium extends from frontal glands posteriorly to male copulatory apparatus. Ovaries paired, ventral; extend from frontal glands posteriorly to bursal nozzle (Figs. 4A, B). Testes paired, lateral to eggs; separate from ovary. Testes extend from frontal gland posteriorly to level of the bursal nozzle (Figs.4A, B). Common genital pore opens with posterior side opening to male copulatory apparatus, and anterior side opening to vagina (Figs. 4A, B, 5C). Vagina is positioned directly anteriorly to the male copulatory organ (Figs. 4A, B, 5C). Vagina surrounded by a large muscular sphincter; leads to seminal bursa with well-developed sclerotized bursal nozzle. Lateral extensions of bursal nozzle cells extend posteriorly to form anterior and lateral portions of seminal bursa wall (Figs. 4B, 5C, 6A). Gonopore opens directly to well-developed, C-shaped tubular penis with outer non-anastomosing longitudinal muscles and inner circular muscles (Figs. 4B, 5C, 6B). Circular muscle fibers are thicker than spaces between fibers. Lumen filled with large spherical glandular secretions (Figs. 4A, B, 5B, C). Penis invaginated into muscular seminal vesicle filled with sperm and small spherical granules that surrounds proximal end of penis.[From Hooge MD, Eppinger N (2005): 6-8]
Diagnosis for the valid (accepted) taxonomic name
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