136 PROCEEDINGS OF THE NATIONAL, MUSEUM vol.88 



Dimensions of one, life : Length 1.05 mm., breadth 0.3 mm. ; diameter 

 of oral sucker 0.09 mm., pharynx 0.045 mm., ventral sucker 0.18 mm. ; 

 ova 0.027 by 0.015 mm. One, collected August 19, 1919 ; dimensions 

 in balsam : Length 1 mm., breadth 0.21 mm. ; diameter of oral sucker 

 0.1 mm., pharynx 0.056 mm., ventral sucker 0.15 mm.; ova 0.027 by 

 0.015 mm. The anatomy is indistinctly shown on account of the 

 uterus, which, crowded with ova, fills the greater part of the body; 

 lobes of vitellaria pyriform. 



From common scup: Two (U.S.N.M. No. 8364), collected July 27, 

 1920. Measurements in balsam: (1) Length 1.26 mm., breadth 0.51 

 mm. ; oral sucker, length 0.1 mm., breadth 0.15 mm. ; pharynx, length 

 0.05 mm., breadth 0.06 mm. ; diameter of ventral sucker 0.28 mm. (2) 

 Length 1.09 mm., breadth 0.47 mm.; oral sucker, length 0.1 mm., 

 breadth 0.13 mm. ; diameter of ventral sucker 0.22 mm. ; ova 0.032 by 

 0.018 mm. 



The genitalia are obscured and more or less displaced by the accu- 

 mulation of ova. The intestinal rami extend to the posterior end, the 

 cells in their walls distinct; genital aperture ventral to pharynx; 

 genital sinus short ; cirrus pouch in front of ventral sucker, inclosing 

 prostate and seminal vesicle; testes a short distance behind ventral 

 sucker, nearly transverse. Ovary not distinctly seen ; in one specimen 

 it appeared to be behind the right testis, in the other behind the left. 

 The lobes of the vitellaria are long and fingerlike. 



The largest ova noted were about 0.036 by 0.018 mm. ; the smallest 

 0.024 by 0.015 mm. 



Genus APONURUS Looss, 1907 



APONURUS species 



Plate 12, Figure 127 



Four small distomes from a specimen of Lohotes surinamensis^ 

 September 1, 1910, are here recorded. 



The distomes were somewhat macerated, and the anatomy is im- 

 perfectly shown in the mounted specimens. So far as the anatomy 

 can be made out these distomes appear to be near the species 

 Aponurus lagimcula Looss (Zool. Anz., vol. 31, p. 608; Zool. Jahrb., 

 vol. 26, p. 169, figs. 53, 54, 77, 78, 1907). 



Body smooth, not differing much in breadth, bluntly rounded 

 posteriorly, slightly tapering anteriorly; ventral sucker much larger 

 than oral; genital pore ventral to pharynx; cirrus pouch short; 

 prostate and seminal vesicle at anterior margin of ventral sucker; 

 testes a short distance back of ventral sucker; ovary behind testes, 

 about middle of post-acetabular region ; vitellaria of several distinct 



