HEOLMINTH PARASITES OF BIRDS — DENTON AND BYRD 165 

 Genus BRACHYLECITHUM Strom, 1940 



BRACHYLECITHUM RARUM (Travassos, 1917) 



Figure 35, d, e 



Lyperosomum raruni Travassos, First Conf. Soc. Sud. Amer. Hig,, pp. 738, 741-742, 



fig. 4 (191G), 1917. 

 Brachylecithum rarum Strom, Parasitol, Sborn. Zool. Inst. Akad. Nauk U.S.S.R., 



vol. 8, p. 183, 1940. 

 Olssoniella rara Travassos, Monogr. Inst. Oswaldo Cruz, No. 2, pp. 217-218, est. 



84, figs. 1-3 ; est. 85, figs. 1-2, 1944. 



Description. — Body of mature specimens large and robust, 4.50 to 

 6.90 mm. long by 0.30 to 0.49 mm, wide between acetabulum and vitel- 

 laria, slightly flattened dorsoventrally, with almost parallel sides and 

 rounded ends. Cuticle aspinose, but with prominent fingerlike tuber- 

 culations irregularly distributed over body except for region anterior 

 to genital pore. Oral sucker subterminal in position, large and mus- 

 cular, 0.28 to 0,38 mm. long by 0.28 to 0.31 mm. wide. Acetabulum 

 weakly muscular, 0.29 to 0.35 mm. long by 0.29 to 0.41 mm. wide, with 

 shallow, saucerlike lumen in living or relaxed specimens, or with cen- 

 ter protruded (fig. 35, e) so as to eliminate lumen in most fixed speci- 

 mens, located in anterior sixth of body. Ratio of width of oral sucker 

 to acetabulum 1 : 1.05 to 1 : 1.34. Prepharynx absent. Pharynx mus- 

 cular, globular, longer than wide, 0.09 to 0.11 mm. long by 0.08 to 0.10 

 mm. wide. Esophagus slender, straight to slightly wavy, bifurcating 

 from one-half to three-fourths of distance from oral sucker to ace- 

 tabulum. Ceca of medium width, fairly thick-walled, straight to 

 slightly wavy, passing dorsal to acetabulum, dorsal to lateral margins 

 of gonads and dorsal to vitellaria, terminating unevenly near body 

 middle, with ends forming distended pouches. Excretory pore 

 terminal. Excretory vesicle thin-walled, tubular, extending anteriad 

 to near anterior limits of vitellaria. Genital pore medium, ventral to 

 intestinal bifurcation. Testes round to oval, equal in size, 0.17 to 0.32 

 mm. in diameter, situated in body midline, with one directly behind 

 the other. Anterior testis separated from acetabulum by three to six 

 transverse loops of uterus; posterior testis usually separated from 

 anterior one by a single dorsoventral loop of uterus. Vasa efferentia 

 arising from dorsomedial surfaces' of testes and uniting just posterior 

 to caudal margin of acetabulum to form an almost straight vas de- 

 ferens. Cirrus sac elongated-pyriform, 0.18 to 0.25 mm. long by 0.07 

 to 0.10 mm. wide, containing a coiled seminal vesicle, ejaculatory duct 

 surrounded by prostatic gland cells and eversible cirrus. One-third 

 to one-half of cirrus sac lies dorsally to acetabulum. Ovary trans- 

 versely oval in shape, 0.11 to 0.18 mm. long by 0.14 to 0.21 mm. wide, sit- 

 uated in middle of body and separated from posterior testis by one to 



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