126 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 83 



Class TREMATODa 

 Family BUCEPHALIDAE Poche, 1907 



RHIPIDOCOTYLE TRANSVERSALE, new species 



Plate 6, Figure 1 



D-escrlpt'wn of immature forms encysted in Menidia. — Size 0.45 

 b}^ 0.24 mm to 1.22 by 0.5 mm. Body oval with broadest region 

 near middle. Anterior half of body covered by mimite spines in 

 transverse rows; posterior part of body with spines inconspicuous, 

 embedded in cuticle. Anterior sucker with its forward-projecting 

 structure cuspidor-shaped; sucker 160/x to 185/^, in diameter, base of 

 sucker 200/a to 2G5/x from anterior end. Very young specimens have 

 a mass of glandular material in anterior end of body ( = " cystogen- 

 ous organ " of Tennent, 1906, and " penetration organ " of Wood- 

 head, 1920). Anterior sucker develops in midst of this mass, and 

 vitelline follicles from posterior part of it. Pharynx about two- 

 fifths length of body from anterior end, about 90/a to IOO/a in di- 

 ameter, Avithout prepharynx. Intestine egg-shaped or nearly 

 spherical, in large specimen about SlO/x in diameter. Testes round 

 or oval, side by side or diagonally situated, somewhat posterior to 

 center of body ; size variable, up to 175/a in diameter. Cirrus pouch 

 about 250^ to 350/* long and 70/i to 125/a in diameter, with a small 

 seminal vesicle at its proximal end, about 50/^ long. Genital atrium 

 large, in a large specimen 180/* long and 120/x in diameter, often 

 nearly filled by the partially everted cirrus. Ovary smaller than 

 testes, usually oval, up to 95/x by 130/*, situated beside or diagonally 

 in front of anterior testis. Developing uterus present in older 

 specimens, with several twists or loops, entering genital atrium be- 

 side cirrus. Vitelline follicles 32 in number, arranged transversely, 

 and not separated into two distinct groups but connected across 

 median line just posterior to anterior sucker. 



Host. — Menidia menidia. 



Location. — In walls of intestine. 



Locality. — Galveston Bay, Tex. 



Type specimen. — U.S.N.M. Helm. Coll. no. 39516; paratypes, no. 

 39517. 



Remarks. — Rhipidocotyle transversale differs from other members 

 of the genus in the form of the anterior sucker and its forward- 

 projecting structure and in the arrangement of the vitellaria, which 

 in all other forms are arranged in two lateral groups. It appears to 

 be identical with the form figured by Linton (1901, pi. 34, figs. 367, 

 368) as " Gasterostomnm sp. from Tylosunts maHnus ", but it is not 

 the same as the one that he recorded from this host at Beaufort, 



