PARASITIC FLATWORMS 



449 



116(115) Rostellum long, slender. Male pores alternate regularly. Female 

 pore, when present, always marginal. 



T atria Kowalewski 1904. 



Rostellum with single crown of 10 to 14 large hooks and behind them 

 numerous rows of small conical hooks. Suckers and posterior portion 

 of head covered with minute spines. Segments not numerous. Cirrus- 

 pouch large. Testes not numerous. Male and female canals pass be- 

 tween longitudinal excretory vessels. Distal end of vagina instead of 

 opening to exterior turns posteriad into next following proglottid and 

 opens into seminal receptacle there. Seminal receptacles median; ac- 

 cessory vagina present opposite cirrus-pouch, sometimes with opening. 

 Adults in birds (Urinatores). 



The type species (Tatria biremis Kowalewski iQO4) occurs in the 

 horned grebe and has not been reported for North America. In 1887 

 Leidy reported Taenia scolopendra Diesing from this host and that species 

 is placed here by some authors. 



FIG. 759. Tatria biremis. Forma major; proglottids with lateral appendages, 

 (After Kowalewski.) 



117(55) External division of strobila into proglottids lacking 118 



118 (119) Anterior portion of strobila folded and coiled to form large pseudo- 

 scolex; strobila grooved transversely, without true pro- 

 glottid limits. . . Family FIMBRIARIIDAE Wolffliiigel 1898. 



Scolex small, unstable, frequently lost, with rostellum armed with single row of hooks. 

 Pseudoscolex conspicuous. Strobila with transverse grooves which produce appearance of 

 segmentation. Three pairs of longitudinal excretory vessels. Reproductive 

 organs not segmentally arranged. Genital pores marginal, irregular, generally 

 unilateral. Testes numerous, arranged in transverse rows. Uterus not persist- 

 ent, breaking down into a large number of egg sacs. Egg spindle-shaped with 

 thin transparent shell. Adults in birds (Anseriformes). 



Type genus Fimbriarto Frolich 1802. 



(Syn. Epision Linton 1892.) 



Two well-known species both occur in North American water birds; a third, 

 F. plicata (Linton) 1892 is recorded from the American scoter. 



FIG. 760. Fimbriaria plicata. Lateral view of head and anterior part of body of 

 smallest specimen. X 8. (After Linton.) 



119 (118) Scolex small, simple. Strobila round or nearly so. Without pro- 

 glottid boundary except at extreme posterior end. 



Family NEMATOTAENTJDAE Liihe 1910 . . 120 



Scolex unarmed, without rostellum. At extreme posterior filiform end of strobila a few 

 separate proglottids visible externally; these are much longer than thick, separate readily, and 

 move about independently a long time. Genital pores alternate irregularly. Gurus and 

 vagina pass dorsal to excretory canals and nerve trunks, open into genital atrium marginal 

 in location. Male organ dorsal, female ventral. 



In intestine of Amphibia. 



