142 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 87 



The total absence of an oral sucker in these two species might be 

 considered sufficient reason for erecting a new genus, but in the absence 

 of other difTerences they should be retained for the present in the 

 genus Amphimerus. 



Genus DIASIA Travassos 



DIASIA FODIENS (Linton, 1928) Ejsmont, 1931 



Synonym: Haematotrephus Jodiens Linton, 1928 (free form). 



Description. — Pachytreminae. Elongate muscular worms, with 

 sides of body more or less parallel, posterior end rounded, anterior 

 end roughly pointed. Total length 11 mm.; greatest width 1.85 mm., 

 near center of body. Near the genital pore the width is 1.4 mm. and 

 at the second testis 1.68 mm. Skin aspinose. Suckers atrophied. 

 Anterior tip of body differentiated into a triangular-shaped protrusible 

 organ (?). Mouth opening subterminal. Pharynx pear-shaped, 0.15 

 by 0.24 mm. Esophagus 0.05 mm. in diameter and 0.45 mm. long, 

 slightly sinuous. Intestinal crura relatively large, thin-walled, and 

 reaching nearly to posterior end; not continuous. Testes entire, 

 subspherical, slightly tandem, in posterior sixth of body; anterior 

 testis 0.35 by 0.56 mm., posterior testis 0.40 by 0.52 mm. Seminal 

 vesicle small, pyriform, in anterior body third, just anterior to anterior 

 margin of uterus, slightly to left of midline; it is 0.16 by 0.58 mm. 

 Copulatory organs absent. Ovary strongly lobed, broader than long, 

 0.22 by 0.70 mm., just anterior to anterior testis. Mehlis' gland 

 anterior and to right of ovary. Seminal receptacle 0.33 by 0.83 

 mm., between ovary and anterior testis. Uterus extending from 

 ovary to posterior border of anterior sixth of the body, confined within 

 the mtestina] crura, and filled with small yellowish eggs. Eggs 

 0.024 by 0.012 mm. Vitellaria extracecal, consisting of small spheri- 

 cal follicles, forming a more or less continuous line from just posterior 

 of the anterior margin of the uterus to posterior of the posterior 

 testis; vitelline ducts arising opposite Mehlis' gland. Excretory 

 bladder Y-shaped. 



Host. — Gavia immer (reported from intestine). 



Distribution.—^ orth America (Woods Hole, Mass.). 



Specimen.— v. S. Nat. Mus. Helm. Coll. No. 7915 (type). 



Remarks.— Tv^o species have been described for the genus Diasia. 

 Travassos (1922) erected the genus to contain the type species D. 

 diasia, from the pancreas of Plotus anhinga in Brazil, kis description 

 of the genus is very brief. Olsen (1938) has described D. podilymhi 

 from the mesenteries of Podilymbus podiceps from North America. 

 He has also amended the generic diagnosis and pointed out the differ- 

 ences in the species. 



