1919] 



Cort: A New Distome from Bona aurora 



291 



difference between the two sj-stenis is in the bladder, which in Ilaplo- 

 metra cylindraeca is shorter than in Margeana calif or niensis and is 

 divided at its anterior end into two lobes. In Haplametra cylindracea 



Fig. 4. Camera lucida drawing of immature specimen of Margeana califor- 

 niciisL?, ventral view; 6., excretory bladder; i., intestinal caecum; o.s., oral sucker; 

 or., ovary; ph., pharynx; t., testis; v.s., ventral sucker. 



the points on each side where the anterior and posterior collecting 

 tubes meet the common collecting tubes from the division of the 

 bladder are at about the mid line of the body, while in Margeana 

 caUforniensis these points are at the posterior limit of the anterior 

 third of the body. This difference produces variations in the positions 



