ID University of Michigan 



The usual structures of tailless cercaria were found except 

 the cephalic glands which if they had ever been present were 

 now absent. With some difficulty in unstained specimens or 

 even in those stained with thionin, haemalum, or erythrosin 

 one can make out a rather weakly muscled oral sucker, slender 

 or broadly oval in outline, followed by a w^eakly muscled 

 phar}^nx, usually slender and difficult to see. A short oesoph- 

 agus gives rise to the intestinal bifurcations which as slender 

 indistinct tubes, sometimes containing a few small non-staining 

 ellipsoidal bodies, extend well into the hinder end of the body. 



The acetabulum is nearly round, shallow, and situated al- 

 ways posterior to the middle of the body. While of fair size 

 it is not a prominent organ. Posterior to the acetabulum but 

 near it is situated a group of deeply staining cells, making a 

 round or somevrhat rectangular rnass measuring about 0.03 X 

 0.026 mm. or even 0.036 X 0.043 ""'"''• -"^ slit like aperture on 

 the ventral surface marks the middle of the mass. The open- 

 ing is probably the genital pore and the mass of cells a portion 

 of the developing sexual organs. The cells are large massively 

 club-shaped, radiating irregularly from the genital orifice. The 

 nuclei of these cells do not stain well but the cytoplasm stains 

 densely with haemalum and diffusely with thionin. Close 

 behind the first mass of cells in some more fully developed in- 

 dividuals ^Fig. 4) lies a second irregularly triangular mass 

 of cells. These cells are indistinct. The mass when well 

 developed measures about 0.032 X 0.035 mm. It lies dorsal 

 to the excretory vessels although in the drawing it appears to 

 lie within the. excretory vessels. 



The excretory system is not well marked and only a small 

 portion of it can be traced. In the hinder part of the body can 

 sometimes be found a small terminal excretory pore by 

 which through a narrow duct the excretory vessels discharge 



