158 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



Genus LYPEROSOMUM Looss, 1899 



LYPEROSOMUM OSWALDOI (Travassos, 1919) 



Figure 35, a-c 



Oswaldoia oswaldoi Travassos, Arch. Esc. Sup. Agr., vol. 3 (1919), pp. 15-17, 



fig. 6, 1920. 

 Lyperosomuni osirahloi Travassos, Monogr. Inst. Oswaklo Cruz, No. 2, pp. 111- 



145, est. 47, figs. 1-5 ; est. 48, figs. 1-5 ; est. 49, fig. 1, 1944. 



Description. — Body of sexually mature specimens (fig. 35, a, h) 

 elongated, slender, 4.35 to 10.65 mm. long by 0.39 to 0.77 mm. wide in 

 testicular zone, semitransparent, slightly flattened dorsoventrally ; 

 preacetabular region short, narrowing abruptly to blunt anterior 

 extremity; postacetabular segment extremely elongated, gradually 

 tapering to rounded posterior end. Cuticle aspinose, with fine trans- 

 verse striations and small retractile sensory papillae, which are usually 

 more clearly visible along margins of body of living specimens. Oral 

 sucker subterminal, 0.15 to 0.30 mm. long by 0.16 to 0.31 mm. wide, 

 preceded dorsally by a short liplike projection. Acetabulum large, 

 0.37 to 0.66 mm. in diameter, strongly muscular, cup-shaped with a 

 deep lumen (fig. 35, &) , located within anterior seventh of body. Katie 

 of width of oral sucker to acetabulum about 1 : 2. Pharynx globular, 

 relatively small, 0.06 to 0.15 mm. in diameter. Length of esophagus 

 approximately equal to diameter of pharynx. Ceca slender, slightly 

 sinuous, unequal in length, terminating one-half to two-thirds distance 

 from vitellaria to caudal extremity of body. Excretory pore terminal. 

 Excretory vesicle thin-walled, tubular, extending anteriad almost to 

 semiinal receptacle, where it receives a common collecting tubule from 

 each side of body. Common collecting tubules passing anteriad 

 laterally to gonads to zone of posterior third of acetabulum, where 

 each branches into an anterior and posterior main collecting tubule. 

 Genital pore approximately median, at level of posterior limits of 

 pharynx. Testes round to oval, 0.11 to 0.30 mm. long by 0.13 to 0.36 

 mm. wide, oblique in position, located close behind acetabulum, in 

 anterior fourth of body. Anterior testis may be on right or left side 

 of body midline. Cirrus sac club-shaped, small, 0.07 to 0.19 mm. long 

 by 0.04 to 0.10 mm. wide, usually lying entirely in front of acetabulum, 

 containing convoluted seminal vesicle, ejaculatory duct surrounded 

 by prostatic gland cells and eversible cirrus. Ovary round to trans- 

 versely oval, 0.07 to 0.27 mm. long by 0,13 to 0.31 mm. wide, situated 

 from 0.10 to 0.35 mm. behind caudal testis and on same side of body as 

 that organ. Seminal receptacle globular, located just posterior to 

 ovary. Mehlis' gland at posteromedial margin of seminal receptacle. 

 Vitellaria lateral in position, composed of numerous small follicles, 

 beginning anteriorly at a level within zone of anterior testis and ex- 

 tending posteriorly for a distance of 1.85 to 4.34 mm., terminating 



