332 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



Family ZOOGONIDAE 



Genus DIPLANGUS Linton, 1910 



DIPLANGUS TRIRADIATUS, new species 



Plate 13, Figures 15, 16 



Description (based on nine mature and eight immature speci- 

 mens from Menticirrhus undulatus and Roncador stearnsi) . 



Length 0.686 to 0.967 mm. One specimen 0.702 mm. in length did 

 not contain eggs although gonads were well developed; another 

 0.686 mm. in length did contain eggs. Body smooth, cylindrical, 

 greatest width or thickness near acetabular level, 0.195 to 0.273 

 mm. Forebody tapering but rounded, hindbody tapering and more 

 pointed. Acetabulum protrusible and in all specimens greatly ex- 

 tended so that the acetabular stalk is almost as long as or even 

 longer than the hindbody ; in one specimen the distance from the 

 acetabulum edge to dorsal wall of body was practically the same 

 as the total body length. Base of acetabular stalk from one-third 

 to one-half body length from anterior end of body. The lateral 

 position of most specimens prevented transverse measurements of 

 the suckers. Oral sucker length 0.093 to 0.099 mm., thickness 0.081 

 to 0.093 mm., width (two specimens) 0.083 to 0.092 mm. Acetabu- 

 lum length 0.135 to 0.172 mm., thickness (one specimen) 0.135 

 mm., width 0.144 to 0.179 mm. Ratio of lengths of oral sucker and 

 acetabulum 1:0.91 to 2. Genital pore (gp, pi. 13, figs. 15, 16) 

 median or submedian, opposite base of pharynx or slightly pos- 

 terior to pharynx. Short prepharynx present ; pharynx often but 

 not always with a median constriction, 0.054 to 0.063 mm. long, 

 0.029 to 0.050 mm. wide or thick. Esophagus (e) longer than 

 pharynx, wide and thin walled. Ceca (ic) sinuous and extending 

 to level of middle of anterior testis, some distance from posterior 

 end of body, or rarely to posterior edge of posterior testis. Ex- 

 cretory pore terminal ; excretory vesicle l-shaped, extending past 

 the posterior testis, ending dorsal to anterior testis. Testes globu- 

 lar, diagonal, about midway between acetabular stalk and posterior 

 end of body. Genital atrium (ga) a short thin-walled tube. Cirrus 

 (cir) thick-walled, bulblike, becoming thin walled just before 

 joining the atrium ; cirrus sac and prostatic vesicle apparently lack- 

 ing ; seminal vesicle tubular, bipartite with a saclike, thin-walled 

 anterior portion (sv^ and a swollen S- or V-shaped tube (sv^) 

 with cellular walls (fig. 16) ; vesicle ending near base of acetabular 

 stalk. Ovary globular, slightly anterior to but overlapping the 

 anterior testis, to left of midline. Seminal receptacle (sr) round, 

 well developed, preovarian. Vitellaria (v) in two lateral clumps 



