162 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



which parallels the course of the cecum to the cirrus sac. The trans- 

 versely oval testes frequently show a distinct indentation of their lat- 

 eral margins. The number of vitelline follicles varies from 8 to 14 

 on each side of the body. Anterior to the level of the ovary the 

 uterus follows the course of the cecum in ascending to the genital pore. 

 The mature ova, 30/i to 34,«, by iT^u, to 21/^,, contain ciliated, styleted 

 miracidia, each with two large, oval, ref ractile vesicles. 



Lutztrema monenteron has been reported previously by Price and 

 Mcintosh (1935) from the gall bladder and bile ducts of the robin, 

 Turdus migratorius Linnaeus, and the bluebird, Sialia sialis sialis 

 (Linnaeus), from Washington, D. C, Virginia, and Quebec, Canada, 

 and by Ishii ( 1942) from the liver of the ruffed grouse, Bonasa umbellus 

 (Linnaeus), and the kingbird, Tyrannus tyrannus (Linnaeus), from 

 Minnesota. Through the kindness of Dr. E. G. Wallace, University 

 of Minnesota, we have been permitted to examine slides numbered 

 G-33-19, G-36-6 (ruffed grouse) and G-36-7, G-36-8 (kingbird) 

 of Ishii's material. Since the mounted specimens' of this material 

 prove to be entirely unsuitable for study it is impossible for us to 

 verify Ishii's identification. The species from the ruffed grouse and 

 kingbird, then, must remain as species inquirenda awaiting further 

 study on more favorable material. 



The present paper reports specimens of L. monenteron from the 

 liver of the robin, Turdus migratorius^ from Mountain Lake, Va. ; 

 Highlands, N. C. ; Augusta, Ga. ; Nashville, Tenn. ; Houston, Tex.; 

 and Marion, Ohio. Fourteen (73.7 percent) of the 19 robins examined 

 by us proved to have flukes of this species in the gall bladder and bile 

 ducts. In addition to the material from the robin, specimens identi- 

 fied as L. monenteron were taken from the gall bladder of two (10 

 percent) of 20 mockingbirds, Mimus polyglottos (Linnaeus), from 

 Augusta, Ga., and Houston, Tex., and from a single (2.4 percent) 

 brown thrasher, Toxostoma rufutn (Linnaeus), from ]\Iountain Lake, 

 Va. Although the specimens from the mockingbird (fig. 34, c) and 

 brown thrasher (fig. 34, d) are slightly smaller, they agree very closely 

 with the form from the robin in (1) shape of the body; (2) ratio of 

 sucker sizes and position of the acetabulum; (3) course and length of 

 the cecum; (4) shape and position of the genital organs; (5) position 

 of the genital pore; and (6) pattern of the uterus in front of the 

 anterior testis. In certain of the specimens from the mockingbird the 

 ova measure as much as 39/x in length, while in other specimens from 

 the same host they fall within the range given for the ova from the 

 robin material. Further evidence that the worm from the mocking- 

 bird is identical with the form in the robin is obtained through life- 

 history studies ; the larval stages of the two forms are indistinguish- 

 able (unpublished data). 



