NO. 14 MANTER : DIGENETIC TREMATODES OF FISHES 375 



SPECIFIC DIAGNOSIS OF PARVACREADIUM BIFIDUM 

 Body smooth, widest at posterior end, tapering from posterior to an- 

 terior end, more rapidly so anterior to acetabulum; posterior end trun- 

 cated and deeply indented medianly to form 2 rounded lobes, right and 

 left. These lobes may bear peculiar papillalike or fingerlilce processes 

 (seen on 2 specimens) (figs. 54 and 55). Body 0.817 to 0.953 in length 

 by 0.360 to 0.450 in greatest width. Forebody narrow and thinner than 

 remainder of body. Oral sucker subterminal, elongated, 0.076 to 0.099 in 

 transverse diameter by 0.085 to 0.110 in length; acetabulum proper 

 nearly circular, 0.127 to 0.178 in diameter, possessing a single large an- 

 terior lobe and a single large posterior lobe overlapping each other to cov- 

 er the acetabular aperture (fig. 52). Edges of lobes with very thick cu- 

 ticula; free edge of posterior lobe extending diagonally backward and out- 

 ward beyond acetabulum (fig. 52). These large, peculiar acetabular lobes 

 seem to have a grasping function. 



Prepharynx possessing an inner circular fold forming a circular ridge, 

 almost or quite meeting in the center (fig. 53) ; pharynx 0.060 to 0.071 

 long, 0.048 to 0.066 wide; esophagus somewhat shorter than pharynx; in- 

 testinal bifurcation about ^ from anterior end of body to acetabulum; 

 ceca reaching almost to posterior end, ending blindly. Genital pore slight- 

 ly to the left, opposite base of pharynx or as far forward as mid-pharynx 

 level. Testes tandem, close together, in posterior half of body, wider than 

 long, slightly irregular in outline. Seminal vesicle slightly coiled, free in 

 parenchyma, at anterior border of acetabulum which it may overlap a 

 short distance; ejaculatory tube nonmuscular, almost straight, uniting 

 with uterus near genital pore ; genital sinus very short, thick walled ; few 

 prostatic cells scattered in region of ejaculatory tube and also near end of 

 uterus. A delicate, rudimentary cirrus sac, continuous with the wall of the 

 sinus, extends a very short distance backward enclosing a few gland cells 

 and a weakly developed cirrus (cirrus sac observed only in sections). 



Ovary transversely ovoid, pretesticular, to the right, close to anterior 

 testis; seminal receptacle lacking; Laurer's canal present but apparently 

 not opening to outside; vitellaria from intestinal bifurcation to posterior 

 end of body, surrounding ceca in hindbody ; uterus preovarian ; eggs large 

 and thin shelled, 51 to 59 by 30 to 34 ju,. Excretory pore median, terminal, 

 between posterior lobes of body; excretory vesicle narrow, extending to 

 posterior testis. 



