194 THE ROYAL SOCIETY OF CANADA 



diameter of oral sucker, 0-40, length, 0-46, of acetabulum, 0-31; 

 centre of latter, 1 • 14 from anterior end. Those from the Channel 

 Cat were considerably smaller and included a number of immature 

 forms. This species was also found encysted around the heart, in 

 the gonads and in the dorsal musculature of the céphalothorax and 

 anterior part of the abdomen of Camharus propinquus Girard from 

 Go-Home and Killarney, Ont., and of C. virilis Hagen from Go-Home, 

 Killarney and Shawanaga, Ont. Although the Small-mouthed 

 Black Bass takes C. hartonii (Fabr.) as well as these two species of 

 crayfish as food at Go- Home, cysts were found only in examples of 

 the latter taken from the preserved stomach-contents of a small 

 number of bass. Furthermore, representative lots of free C. bartonii 

 from the above locations as well as from the Don River, at Toronto, 

 were examined, but no cysts were met with. Crayfish, sp. ?, were 

 also recorded from the stomach of the ChanneKCat from Flat- Rock 

 Lake, but none were examined for cysts. The latter, themselves, 

 ranged in diameter from 0-37 to 2- 0mm., while the largest 'worm 

 taken from a cyst and fixed (in an extended condition) measured 

 2-9 X 0-46. Eggs were seen to be extruded from the worms in all 

 cysts above a diameter of 0-86mm. They were so numerous as to 

 occupy considerably more than half the volume of the largest cysts 

 and to give them the peculiar dark-brown color which permits of their 

 being so easily recognized with the unaided eye. 

 22. Crepidostomum laureatum (Zeder). 26, p. 490. 



Intestines of Perca flavescens (Mitchill), Perch; Eupomotis gih- 

 bosus (L.), Sunfish; Boleosoma nigrum (Raf.), Johnny Darter; and 

 Etheostoma iowae Jor. & Meek. 



A small number of mostly immature specimens from each of the 

 above hosts are referred to this species chiefly on account of the fact 

 that in all of the largest the ventral pair of papillae are, unlike those 

 of the foregoing species, considerably smaller than the remaining two 

 pairs (Fig. 14), although, "originating close together under the anterior 

 end of the mouth sucker, they curve backwards and outwards, mous- 

 tache-like, across the corners of the mouth until their outer, bluntly 

 pointed ends project laterally past the sides of the sucker and posterior 

 to the level of the other papillae," thus resembling those of Acrodactyla 

 petalosa (Lander) as described by Stafford (loc. cit., p. 491). Further 

 resemblances to the latter species are: The position of the genital 

 opening about half way between the suckers; "ovary close behind and 

 to one side of the ventral sucker;" "testes close together, half way 

 between ventral sucker and posterior end," irregular in outline (also 

 characteristic of C. laureatum) and somewhat oblique; "vitellaria from 

 pharynx to posterior end." On the other hand, the ventral sucker in 



