36 ILLINOIS BIOLOGICAL MONOGRAPHS [254 



These flukes are 16 to 18 mm long by 4 to 4 . 5 mm broad. The margins 

 of the body are practically parallel in the posterior two-thirds of the body. 

 The anterior one-third tapers to a weakly rounded point. The subterminal 

 mouth is surrounded by a weakly developed sucking musculature which 

 is approximately three times the size of the small pharynx. The small 

 ovoid pharynx measures 231 ju broad by 281 M long. The slender esophagut 

 which is curved in the form of an S measures 33 1// in length. It opens inso 

 the middle of the dorsal side of the intestinal bifurcation. The voluminous 

 intestinal crura run parallel to the margins of the body throughout their 

 entire course. The vitellaria are moderately developed and occupy the 

 region lateral to the crura. They extend laterally to the inner wall of the 

 crura and fold both dorsally and ventrally around them. They extend an- 

 teriorly not quite to the most anterior portion of the intestinal bifurcation 

 and are separated at the posterior end only by the excretory bladder. The 

 uterus fills the entire space between the intestinal crura. It lies in the 

 mid dorso-ventral region, is profusely coiled and does not extend out 

 beyond the inner wall of the intestine. Genital glands are confined to 

 the posterior intestinal arch. The posterior testis is situated in the middle 

 line of the body and lies directly in the arch formed by the intestine. 

 The anterior testis is a little removed and is contiguous to the crura. They 

 are equal in size and measure 877 to 910ju in diameter. The much smaller 

 ovary lies on the side of the body opposite to the anterior testis and in a 

 transverse plane between the two testes. It is spherical and measures from 

 380 to 390/z in diameter. Dorsally and on the inner posterior side of the 

 ovary is a small spherical receptaculum seminis 82 to 99/x in diameter, 

 which joins by a short duct the oviduct shortly after its emergence from 

 the ovary. Laurer's canal is not present. As the oviduct passes poste- 

 riorly into the adjacent shell gland aggregate it is joined by the vitelline 

 duct. At this point the oviduct enlarges to form the ootype. Just after 

 the uterus emerges from the compact shell gland a second enlargement is 

 seen, the receptaculum seminalis uterinum. It extends posteriorly to the 

 crura where it doubles on itself and pursues its coiled winding course to the 

 genital pore which is situated ventral to the middle region of the pharynx. 

 The cirrus pouch is 182/z broad by 331 /x long and reaches to the middle 

 of the intestinal crura at their bifurcation. The genital pores open sep- 

 arately into a small genital atrium. Eggs thick shelled ovals, 66 by 117^ 

 when fully mature. They contain in the anterior portion of the uterus well 

 developed miracidia as evidenced by the dark eye spots. 



Habitat: Thoracic cavity Host: Gallinago wilsoni 



Locality: Westchester, Pa. Date: 1885 



Collector: Dr. H. W. Warren No. 106 Leidy Collection. 



A comparison of this material with the data given by Stossich (1902: 

 13) and by Kossack (1911:510) for Cydocoelum mutabile (Zeder) as well as 



