46 ILLINOIS BIOLOGICAL MONOGRAPHS [264 



Habitat: In lung and along the Host: Straight-billed Curlew 



back in the abdomen. 



Collector: W. E. Allen No. 08 . 180 Ward collection 



Cydocoelum macrorchis differs from Cyclocoelum mutabile in that the 

 uterus in the former is not restricted to the intercecal space and that the 

 oral sucker is larger than the pharynx, where as in Cyclocoelum mutabile 

 the vitellaria are more heavily developed and the genital glands are smaller. 

 Cyclocoelum macrorchis, however, has a much more muscular and much 

 thicker and heavier body. 



CYCLOCOELUM TRIANGULARUM nov. spec. 

 [Figure 10] 



Medium sized worms 8 mm long by 2.5 mm wide in maximum. Body 

 lanceolate in form. Oral sucker weak, 260/z in diameter, only a little 

 larger than the pharynx which is longer than broad, measuring 248 n in 

 length by 215 M in breadth. The length of the esophagus is approximately 

 one- tenth of the entire body length. Intestinal crura simple. Genital 

 pore ventral to the posterior end of the pharynx. Cirrus pouch extending 

 to the middle of the intestinal bifurcation. The vitellaria extends from the 

 posterior end of the cirrus pouch almost to the excretory bladder at the 

 posterior end of the worm. In lateral extent they pass over the wall 

 of the crura to the middle of that organ. The genital glands lie in the 

 posterior arch of the intestine and are not separated by uterine loops. 

 The two testes lie on the same level, one in either side of the arch, are 

 spherical and equal in size. They measure 41 3 ^ in diameter. The ovary 

 lies anterior to the testes and in the middle line of the body. It is a little 

 more than one-half the size of the testes, is spherical in form and measures 

 248 /z in diameter. The shell gland lies between the ovary and testes also 

 in the middle line of the body and measures 264 ^ in width by 314/j in 

 length. The receptaculum seminis is situated anterior to the shell gland 

 and dorsal to the ovary. Like the ovary the receptaculum seminis is 

 spherical in form and measures 132/* in diameter. The eggs are thick 

 shelled ovals 132 n long by 75 /i wide. 



Habitat: Abdominal air sacs Host: Tringa maculata 



Locality: Creston, Iowa Date: September 4, 1895 



Collector: W. C. Hall No. 21.88 Ward collection 



As was stated in another section of this paper Cyclocoelum triangularum 

 shows a striking similarity to Cyclocoelum wilsoni and is distinguished from 

 that species by the generally smaller body, the more nearly equal sucker 

 and pharynx, the testes of equal size and the relative size of the testes and 

 ovary which in Cyclocoelum triangularum have a ratio of 10:7. It is more 

 nearly equal in size with Cyclocoelum tringae but is distinguished from 



