Paranoplocephala troeschi, New Species of Cestode from the Meadow Vole, Microtus p. pennsylvanicus Ord

Abstract

Diagnosis: Length from 4.5 to 10.0 mm (av. 7.0 mm); width 1.0 to 2.2 mm (av. 1.8 mm). Scolex 0.576 to 0.810 mm in diameter (av. 0.710 mm); 0.360 to 0.594 mm long. Suckers circular, mobile; 0.360 mm in diameter. Scolex nearly square in cross section; slight grooves between suckers, deeper dorsally and ventrally. Short neck present. Longitudinal excretory vessels lie in same transverse plane; 0.016 and 0.012 mm in diameter, the smaller lateral to larger; both forced ventrally by enlargement of seminal receptacle. Transverse canal 0.016 mm in diameter. Genital pores unilateral, dextral, at about middle of segment; genital ducts dorsal to excretory vessels. Cirrus sac averages about 0.168 mm long by 0.066 mm wide; central constriction present. Internal seminal vesicle fills medial bulb of cirrus sac; medial bulb becomes larger than lateral. Vas deferens enlarges to form external seminal vesicle before entering cirrus pouch. Cirrus spinose. Testes extend from longitudinal excretory ducts to just past aporal edge of vitelline gland; 35 to 40 in number; average 0.042 mm in diameter. Testes do not extend anterior to uterus. Vagina ventral to and slightly posterior to cirrus sac; extends medially, enlarging at level of aporal end of cirrus sac to form seminal receptacle. Latter extends dorsally past ovary to poral edge of vitelline gland. Seminal receptacle begins to fill at about middle of strobila; after reaching maximum size of about 0.600 by 0.250 mm it decreases in size and disappears near end of strobila. Anlage of ovary visible in first segment. Ovary situated at about middle of segment, slightly poral; lobate.