322 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



testicular space 0.523 to 0.577 mm. Seminal vesicle (sv) a rela- 

 tively narrow sinuous tube extending from near the genital pore 

 posterior to acetabulum almost to ovary ; cirrus very short ; cirrus 

 sac lacking; a few gland cells (pi. 12, fig. 7) in region of genital 

 pore. Ovary globular, smooth, immediately pretesticular, slightly 

 to the right; seminal receptacle lacking; sperm cells in uterus; 

 Mehlis' gland very large and conspicuous; vitelline follicles (v) 

 large, extending from a point about midway between pharynx and 

 acetabulum continuously to posterior end of body, surrounding the 

 ceca. Uterus preovarian; metraterm lacking; eggs 90 to 92jii by 

 36 to 47/A, when uncollapsed 90 to 92;^ by 43 to 47/x. Excretory 

 vesicle extending to posterior edge of ovary. 



Host. — Gibbonsia metzi Hubbs, weed sawfish. 



Location. — Intestine. 



Holotijve.—V.S.^.M. Helm. Coll. No. 37145. 



Discussion. — The genus Pseudopecoelus contains the following 

 species: vulgaris (Manter, 1934) Von Wicklen, 1946; japonicus 

 (Yamaguti, 1938) Von Wicklen, 1946; elongatus (Yamaguti, 

 1938) Von Wicklen, 1946 ; tortugae Von Wicklen, 1946 ; priacanthi 

 (MacCallum, 1916) Manter, 1947. P. gibbonsiae differs from all 

 these in that its vitellaria extend anterior to the acetabulum. 

 P. vulgaris and P. japonicus have a lobed ovary. P. elongatus has 

 a more posterior genital pore and smaller eggs, and its vitellaria 

 are interrupted opposite the gonads. P. tortugae has a more pos- 

 terior genital pore, much longer hindbody and uterus, and smaller 

 eggs. P. priacanthi has a different sucker ratio and much smaller 

 eggs. 



PSEUDOPECOELUS UMBRINAE, new species 



Plate 12, Figures 8, 9 



Description. — This species has the generic characters of Pseu- 

 dopecoelus, namely: smooth body; acetabulum without papillae; 

 no accessory sucker; ceca ending blindly; no cirrus sac; short 

 cirrus; and tubular seminal vesicle. Length 1.037 to 2.420 mm.; 

 greatest width (near posterior end or at acetabular region) 0.460 

 to 0.873 mm. Body tapering from acetabular level to anterior end, 

 broadly rounded posteriorly. Forebody 0.292 to 0.584 mm. in 

 length or approximately one-fourth body length; a little greater 

 or a little less than posttesticular space. Oral sucker 0.124 to 0.190 

 mm. in transverse diameter; acetabulum 0.219 to 0.365 mm. in 

 transverse diameter, slightly wider than long, with transverse 

 aperture. Sucker ratio 1:1.65 to 2. Acetabulum usually slightly 



