493 



rounded ovary in centre of post- acetabular body. Large elliptical 

 testes dividing the distance behind — the last one reaching very 

 close to the end. Genital pore close in front of ventral sucker. Large 

 penis-sack reaching some distance behind sucker. Uterus in close 

 transverse folds from this to the ovary where it turns to one side, 

 passes between ovary and first testis, down the other side, and fills 

 the space between the two testes even lapping down the sides of the 

 latter. Vitellaria lateral from near posterior end of penis-sack to near 

 anterior testis. 



òO)Centr ovarium lohotes Mac Galium. 

 Stomach, Esox lucius L. (Pike). 



Stizostedion vitreum Mit. (Dory). 

 New genus; centrum, centre; ovarium, ovary. 2,25X0,70. Cigar 

 shaped, rounded ends. Ventral sucker a little larger than oral and 

 one-third the way back. Rosette-shaped ovary in centre of body. 

 Caeca ending opposite centre of ovary. Testes behinds ends of caeca, 

 not conspicuous. Vitellaria lateral, from oesophagus to behind testes. 



51) Clinostomum gracile Leidy. 



Encysted on gills, Perca flavescens Mitv (Perch). 



Coiled up in thin transparent cysts 2 mm across. When free, very 

 active, extending to 6 or 8 mm long and 1 to 2 mm broad. One 

 large specimen found free but coiled int a milk-white globule. It 

 could extend to 12 mm. Killed, it measures 4,25X1,8. Milky-white 

 and opaque with two dark stripes marking the position of the caeca. 

 Under low power the parts between and outside the caeca filled with 

 smoky reticulations. 



52) Allocreadium isoporum Looss? 



Intes, Semotilus huUaris E,af. (Chub). 2,28X0,68. 



53) PlagiopoTus serotinus. 



Intes. Moxostoma macrolepidotum Le S. (Large-scaled Sucker). 



New genus, new species: relay loç, obligue; tzOqoç, pore; serotinus 

 late. 



1,62X0,43. Fusiform, broadest at ventral sucker, ends narrowed, 

 ventral sucker 1,5 times breadth of oral, in front of middle of body. 

 Oral 0,138, ventral 0,231, distance from anterior end 0,646. Skin 

 smooth. Oesophagus twice length of pharynx. Caeca to posterior 

 end. Testes, one close behind the other in the centre of the post- 

 acetabular body. Ovary small, close in front and to one side of first 

 testis, uterus between testes and sucker but my specimens contain 

 no eggs. Penis-sack extends from ventral sucker across the right 



