178 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



(1) size, shape, and relative position of suckers; (2) ratio of sucker 

 sizes (1:1.0 to 1.1); (3) position of genital pore; (4) size, shape, 

 and relative position of the genital organs; (5) number and size of 

 vitelline follicles; and (6) the course of the uterus in ascending to 

 genital pore. In general, specimens from the crow are slightly wider 

 and thicker in proportion to length than specimens from birds of the 

 family Icteridae (blackbirds). The material from the hawk is still 

 wider and thicker in proportion to the length than are those from the 

 crow. There seems, then, to be some evidence to indicate that there 

 is a definite correlation between the size of the host (and its bile ducts) 

 and the size of the specimens of this species that parasitize it. 



The specimens from the hawk measure 2.28 to 2.90 mm. long by 0.38 

 to 0.52 mm. wide. The cuticle of some specimens shows fine trans- 

 verse striations. The weakly muscular acetabulum shows a shallow, 

 saucerlike lumen in some specimens, while in others the center is pro- 

 truded so as to obliterate the lumen. The vasa efferentia arise from 

 the dorsomedial surfaces of the testes and unite just in front of the 

 anterior testis, at the caudal margin of acetabulum, to form a short 

 vas deferens. A specimen has been deposited in the United States 

 National Museum, Helm. Coll. No. 37123. 



Since B. americanum has not been reported previously from any 

 species of hawk, it is considered to be a rare parasite of this avian 

 group. Denton and Rausch (1949) failed to find a single specimen 

 of the species in 160 hawks, 8 of which were of the red-shouldered 

 variety. 



BRACHYLECITHUM STUNKARDI (Pande, 1939), new combination 



Figure 38, h 



Lyperosomum stunkardi Pande, Proc. Nat. Acad. Sci. India, vol. 9, pp. 16-19, 



figs. 1-2, 1939. 

 Olssoniella stunkardi Travassos, Monogr. Inst. Oswaldo Cruz, No. 2, p. 221, est. 



88, fig. 4 ; est. 85, fig. 3, 1944. 



Description — Body muscular, cylindrical to slightly flattened, 

 with rounded anterior and tapering posterior ends, measuring 2.82 

 to 3.98 mm. long by 0.22 to 0.30 mm. wide in region of vitellaria. 

 Cuticle thick, aspinose, finely wrinkled transversely. Oral sucker 

 0.16 to 0.23 mm. in diameter, muscular, subterminal to a short lip- 

 like projection. Acetabulum 0.19 to 0.28 mm. long by 0.22 to 0.35 

 mm. wide, located one-sixth to one-seventh of body length from an- 

 terior end ; fairly muscular, somewhat protrusible, with center often 

 protruded so as to obliterate its lumen ; with a small, flat appendage 

 on each lateral margin. Eatio of width of oral sucker to acetabulum 

 1 : 1.35 to 1 : 1.75. Pharynx muscular, 0.05 to 0.07 mm. in diameter. 

 Esophagus in relaxed specimens narrow, 0.20 to 0.32 mm. long. 



