299] PSEUDOPHYLLIDEA FROM FISHES— COOPER 11 



KEY TO FAMILIES, SUBFAMILIES, GENERA AND SPECIES 



or PSEUDOPHYLLIDEA FROM FiSHES DESCRIBED IN THIS PaPER 



1 (14, 15) Eggs with thick shells and opercula. Opening of cirrus and vagina 



on the same surface as that of the uterus and ahead of it or marginal. 

 Family DIPHYLLOBOTHRIIDAE Liihe 1910 . . 2 



2 (11) Opening of cirrus and vagina surficial 3 



3 (8) Genital openings always on the same surface of the strobila . . 4 



4 (7) Scolex very short, not distinct from the strobila. 



Subfamily LIGULINAE Luhe 1899 .. 5 



5 (6) Segmentation confined to the anterior end, or (in larvae) 



absent Ligula Bloch 1782 



Type and only species: L. inteslinalis (Linnaeus 1758) , . p. 18 



6 (5) Segmentation complete even in the larval stages. 



Schistocephalus Creplin 1829 

 Type and only species. 



Schistocephalus sc'Hdus {O.Y.MuWex 1776) . ... p. 30 



7 (4) Scolex (secondary, see below) similar in shape to the first proglottis ; 



no neck; segmentation beginning immediately behind the scolex, 

 but confined to the anterior end of the worm. 



Subfamily HAPLOBOTHRIINAE Cooper 1917 . . p. 42 

 Type and only genus . . Haplobothrium Cooper 1914 . , p. 43 

 Type and only species: H. globuliforme Cooper 1914 . . p. 44 



8 (3) Genital openings of different segments not on the same surface, but 



alternating irregularly from one surface to the other. External 

 segmentation little expressed. 



Subfamily CYATHOCEPHALINAE Liihe 1899 .. 9 



9 (10) Scolex an unpaired, terminal, funnel-shaped organ. 



Cyathocephalus Kessler 1868 

 Only American species: C. americanus Cooper 1917 . . p. 53 



10 (9) Scolex with two almost spherical bothria, the apertures of which 



may be separated or more or less completely fused to form a 



single terminal opening .... Bothrimonus Duvernoy 1842 



Only American species: B. intermedius Cooper 1917 , . p. 63 



11 (2) Opening of cirrus and vagina marginal. 



Subfamily TRIAENOPHORINAE Liihe 1899 . . 12 



12 (13) Scolex armed with four three-pointed hooks. 



Triaenophorus Rudolphi 1793 

 Only larval forms of two specific types present p. 82 



13 (12) Scolex sagittate, or replaced by a pseudoscolex. Segmentation 



strongly expressed, the individual proglottides very short with 



leaf-like free lateral portions Fistulicola Liihe 1899 



Only American species: F. plkahis (Rudolphi 1819) ... p. 89 



