HELMINTH PARASITES OF BIRDS — DENTON AND BYRD 169 



region between acetabulum and vitellaria. Cuticle tliin, aspinose, 

 smooth except for small, conical, sensory papillae along margins of 

 suckers and on lateral margins of body in some specimens. Oral 

 sucker subterminal to a small liplike projection, weakly muscular, 

 usually elongate oval in shape, measuring 0.07 to 0.16 mm. long by 

 0.08 to 0.15 mm. wide. Acetabulmn somewhat protrusible, weakly 

 muscular, slightly lemon shaped in frontal view but without prom- 

 inent auricular appendages, with shallow, saucerlike lumen (fig. 36, c) 

 in some specimens or with center protruded (fig. 36, h) in others, 

 obliterating lumen ; located in anterior body fifth and measuring 0.10 

 to 0.18 mm. long by 0.11 to 0.20 mm, wide. Ratio of width of oral 

 sucker to acetabulum 1 : 1.0 to 1 : 1.4. Prepharynx absent. Pharynx 

 muscular, globular, longer than wide, 0.03 to 0.05 mm. long by 0.03 

 to 0.04 mm. wide. Esophagus very thin-walled, slender, straight to 

 slightly wavy, relatively long, bifurcating from one-half to two-thirds 

 of distance from oral sucker to acetabulum. Ceca thin-walled, slen- 

 der, straight to slightly wavy, passing dorsally to acetabulum, dorsally 

 to lateral margins of gonads, dorsally to vitellaria, terminating 

 unevenly as slightly distended tubes from a short distance posterior to 

 vitellaria to midway between vitellaria and posterior end of body. 

 Excretory pore terminal. Genital pore median, ventral to intestinal 

 bifurcation. Testes elongated-oval to kidney-shaped, approximately 

 equal in size, 0.09 to 0.27 mm. long by 0.07 to 0.19 mm. wide, situated 

 one directly behind other and occupying almost entire width of body 

 at their levels; depending on state of constriction of body, anterior 

 testis separated from acetabulum by one to four loops of uterus; 

 posterior testis contiguous to anterior testis or separated from it by 

 a single uterine loop. Cirrus sac elongated-pyriform, 0.12 to 0.16 mm. 

 long by 0.04 to 0.06 mm. wide, containing coiled seminal vesicle, ejac- 

 ulatory duct, and eversible cirrus, extending posteriorly far enough for 

 one-third to one-half its length to lie dorsally to acetabulum. Ovary 

 oval, 0.05 to 0.12 mm. long by 0.06 to 0.16 mm. wide, situated near 

 middle of body and separated from posterior testis by one to three 

 uterine loops. Seminal receptacle small, globular, situated entirely 

 posterior to ovary, near either margin of body. Mehlis' gland diffuse, 

 located posteromedial to seminal receptacle. Laurer's canal opening 

 on middorsal surface at caudal level of seminal receptacle. Vitellaria 

 consisting of 6 to 10 large oval to irregular follicles on each side of 

 body (sometimes fusing together to form large irregular masses of 

 yolk cells), occupying zone immediately posterior to Mehlis' gland. 

 Uterus greatly convoluted with loops rather indistinct, filling body 

 posterior to vitellaria, then passing anteriorly between and ventrally 

 to vitellaria, ventrally to one margin of ovary, to dorsal side between 

 ovary and posterior testis, dorsally to both testes and acetabulum to 



