260 Mr. W. Nicoll on the 



Jagcrskiokl's description of the structure of the genital 

 sucker is accurate enough^ but his representation in fig. 1 

 does not give a true idea of its external appearance. Three 

 main groups of muscle-fibres are seen: (1) those forming 

 the genital cup itself, consisting of radial and circular fibres ; 

 (2) those forming the ventral sucker, consisting almost 

 entirely of radial fibres; (3) those associated with the 

 common aperture. These are situated almost entirely in 

 front of the aperture, very few fibres passing backwards. 

 Two well-marked circular bands corresponding to Jager- 

 skiold's HQM, VQ,M, fig. 2, pass almost three-quarters 

 round the aperture. In addition from the sides and anterior 

 border of the aperture there pass out numerous radial fibres. 

 Of these the lateral fibres become lost in the surrounding 

 tissue, but the* anterior fibres pass over and round the ventral 

 sucker and seem to have a certain degree of connection with 

 it. The ventral sucker is almost separated from the genital 

 sucker by a constriction partly surrounded by a sort of 

 sphincter. In extended states of the animal the passage 

 between the ventral sucker and the genital cup appears as a 

 narrow tube. 



The vesicula seminalis is more voluminous than Jager- 

 skiold has it. It does not reach as far back as the ovary. 

 At its anterior end there is a distinct constriction where it 

 passes into the pars prostatica. The latter forms an almost 

 semicircular (U-shaped) loop directed backwards. The 

 ascending limb narrows gradually into the ductus ejacu- 

 latorius, which passes straight forward to the genital sucker. 



The ova measure •047-019 x •022--025 mm. 



Genus Cryptocotyle (Liihe). 



Liihe gives no definition of this genus, so I offer the 

 following : — 



Body flattened, expanded ; outline oval, slightly pointed 

 anteriorly, rounded posteriorly, margin usually irregularly 

 crenated. Cuticle entirely covered with small scales. Ventral 

 sucker small, situated within the large genital sucker, and 

 only slightly differentiated from it. Cavity of genital sucker 

 simple, with no " plug-shaped body.^' Vesicula seminalis 

 not very voluminous ; pars prostatica ? Testes side by side^ 

 symmetrical near hind end of body; posterior border more 

 or less indented. Receptaculum seminis well developed ; 

 Laurer's canal ? Ovary irregular, lobed, on right or left side 

 of middle line. Uterus between testes and genital sucker 

 forming two or more transverse folds which stretch between 



