1911] Watson: The Genus Gyrocotyle. 367 



most of the space. In front and to either side of it, running 

 forward to the posterior margin of the sucker, are the follicles 

 of the testes. Peripheral to these, running out into the lateral 

 folds, are the follicles of the vitellaria, distributed from the 

 acetabular region to the base of the posterior rosette. Along 

 the dorsal surface and to the left of the uterus runs the vagina, 

 leading to the large receptaculum seminis (rec. sem.) located 

 just posterior to the uterus. On each side of the receptaculum 

 seminis lie the follicular ovaries (ovar.) ; immediately in front 

 of it are the vitelline ducts (vit. d.) and the first coils of the 

 uterus. The shell-glands (sh. gl.) are found around these ducts. 

 It is in this region that the ova are fertilized, unite with the yolk- 

 cells and receive their shell-coating. Behind the receptaculum 

 seminis and the ovaries lies the ventral opening of the rosette 

 canal. This structure may be regarded as consisting of two 

 parts. The first is a flaring " funnel," its opening terminal, its 

 margin frilled and folded till it resembles a carnation, or as the 

 Germans put it, a "Kohlkopf." This funnel passes directly 

 acetabulad ; it leads into a narrow canal, which turns at almost a 

 right angle to the course of the funnel, passing to the ventral 

 surface (pi. 34, fig. 15). This ventral opening I have called the 

 " canal opening" (can. op., pi. 46, fig. 76), in distinction from 

 the terminal funnel opening above described. Funnel and canal 

 together are called by German workers the ' ' Trichter ' ' ; Spencer 

 speaks of the funnel-margin as the " rosette" and calls the canal 

 opening the "proboscis." 



Gyrocotyle fimbriata (pi. 48, figs. 80, 81), while bearing a 

 general resemblance to the described species of the genus, differs 

 markedly in certain external characteristics. The body in ex- 

 panded condition is about four times as long as wide ; the lateral 

 frills never totally disappear in any stage of expansion, but can 

 be distinguished from the median portion of the body under all 

 conditions. They are about one-fourth the total width of the 

 body in depth. In contracted specimens the folds of the two 

 sides are invariably drawn toward each other on the ventral 

 (canal opening) surface. The posterior terminal rosette (post, 

 ros., pi. 34, figs. 10, 12-15), is from one-half to three-quarters the 

 greatest width of the body in transverse diameter. Its depth is 



