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PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 88 



Wliile the food of young winter flatfish was being studied in the 

 summers of 1915 and 1916, a record was kept of the distomes found. 

 With few exceptions these distomes were referred to the species 

 nomalometron pallidum (U.S.N.M. No. 8296) and Eemiurus appen- 

 diculatus. The appendiculates, for the most part, came from the 

 stomachs, the others from the intestines of their hosts. 



Twenty-three, collected August 9, 1923 ; eight fishes examined. 



Twelve, collected July 29, 1929. Smallest, length, 1.60 mm.; 

 breadth, 0.53 mm.; largest, length, 3.20 mm., breadth, 0.77 mm.; 

 ova, 0.09G by 0.042 mm. 



These distomes from the winter flatfish, representing as they do 

 a great variety of forms, agree in all essential particulars with this 

 species as defined in the foregoing descriptions. Such differences 

 as exist may be accounted for by differences in age and in contrac- 

 tion conditions. Thus, in distomes of the same lot there are some 

 in which the seminal vesicle and seminal receptacle are clearly de- 

 fined, some in which the seminal vesicle cannot be made out, some in 

 which the seminal receptacle cannot be seen, and some in which 

 neither of the seminal vessels can be distinguished. Evidently con- 

 ditions varying from plethora to emptiness account for the apparent 

 variation in these organs. In like manner differences in states of 

 contraction, especially of the neck, explain many apparently radical 

 differences in relative proportions. Differences harder to reconcile 

 are seen in a tendency of the testes to be more or less lobed. Also, 

 the ventral sucker tends in some to be a little larger than the oral 

 sucker. (U.S.N.M. No. 8297.) 



Table 2G. — Measurements of six specimens of Homalouietron pallidum in halsam 



Measurement 



Length 



Maximum breadth 



Oral sucker, length 



Oral sucker, breadth 



Length of prepharynx... 



Pharynx, length 



Pharynx, breadth. 



Length of esophagus 



Ventral sucker, length. . 

 Ventral sucker, breadth 

 Ova, 0.09 by 0.06. 



Mm. 

 3.75 

 .52 

 .32 

 .22 

 .28 

 .21 

 .14 

 .16 

 .36 

 .22 



From tautog: One, collected April 26, 1915. Measurements in 

 balsam: Length, 0.81 mm.; breadth, 0.35 mm.; diameter of oral 

 sucker, 0.15 mm., of pharynx, 0.08 mm., of ventral sucker, 0.15 mm. 



