Cyclocoelidae Stossich, 1902

Dronen, Norman O., 2007, Revision of the family Cyclocoelidae Stossich, 1902 with the proposal of two new subfamilies and the description of a new species of Morishitium Witenberg, 1928 from the common snipe, Gallinago gallinago, from Texas, U. S. A., Zootaxa 1563, pp. 55-68 : 58-59

Family Cyclocoelidae Stossich, 1902

Diagnosis: Medium-sized to large flatworms, lanceolate, body often tapered anteriorly and rounded posteriorly. Oral sucker, if present, usually poorly developed. Acetabulum generally absent, but reported in some species. Mouth subterminal, prepharynx generally shorter than esophagus, ceca frequently simple, inner wall sometimes irregular, undulating in overall appearance in some species, united near posterior extremity to form characteristic cyclocoel. Testes oval to elongate, borders smooth or irregular, tandem to diagonal, rarely side by side, usually located near posterior end, but may be equatorial to preequatorial in some species. Genital pore near midline of body, prepharyngeal, pharyngeal or postpharyngeal. Cirrus sac present, inclosing seminal vesicle, extending posteriorly to level of posterior aspect of esophagus to immediately postbifurcal. Ovary oval to elongate, intertesticular, pretesticular or posttesticular, forming a triangle or in a straight line with testes. Uterus intercecal to extracecal, uterine seminal receptacle (“ receptaculum seminis uterinum ” of Yamaguti [1933]; “ receptacle seminalis uterinum ”of Harrah [1922]) present in some species. Vitellaria follicular, ventral and somewhat lateral to ceca, vitelline fields reaching to, or beyond, cecal bifurcation anteriorly, confluent posteriorly or not. Excretory vesicle generally Y-shaped, branches extending anterior to level of pharynx or beyond, reticulate where known. Excretory pore usually somewhat subterminal opening on dorsal surface, may approach being terminal in some species. Life cycles, where known, utilize either freshwater or terrestrial snails, polyembryony produces tailless cercariae that encyst in either the rediae where they were produced or in the tissue of snails. Adults in body cavity, lungs, air sacs, nasal and infraorbital sinuses, or hypothalamus of birds, occasionally in mammals.

Type genus: Cyclocoelum Brandes, 1892 .