31 6 ERNEST CARROLL FAUST. 



The esophagus is short; it is surrounded by a small bulbous 

 pharynx just at the point where it opens into the diverticula. 

 The latter extend caudad as far as the excretory pore and are 

 usually undulatory in the adult larva. The genital organs are 

 represented by four cell masses along the median line, suggesting 

 ovary, testes and cirrus sac. Chords of cells run from the genera- 

 tive organs to the genital pore. Two large eye-spots are situated 

 dorsad in the plane where the divericula originate. They are 

 composed of oval "lenses" surrounded by a mass of melanoidin 

 granules. Dense patches of granules entirely obscure this region. 

 Cystogenous granules form dense aggregates in the connective 

 tissue of the worm. On placing the fluke in water they are freely 

 thrown out and soon dissolve to form a mucus cyst capsule. 

 Meanwhile the tail is easily loosed from the body and cast aside. 

 This species probably belongs to the subfamily Diplodiscinse. 



Cercaria convoluta develops within a redia with conspicuous 

 "feet" and a large irregular pouch-like gut. The pharynx at 

 the anterior end of the redia is small. An inconspicuous birth- 

 pore is present. The redia may reach a length of 1.5 to 2 mm. 



While the above description suffices to separate Cercaria 

 convoluta from previously described cercariae, this species is most 

 strikingly delimited by the convolutions of the main excretory 

 tubules of the cercaria. The excretory pore is located just in 

 front of the anterior margin of the acetabulum. It is surrounded 

 by a strong sphincter, and opens into a small bladder. From 

 the latter organ a single median longitudinal canal runs caudad 

 for about two-thirds the length of the tail. It then bifurcates, 

 each fork opening to the exterior in the distal fifth of the tail. 

 Immediately in front of the bladder is a horizontal collecting 

 tubule which receives the excretory products from right and left 

 sides. As this tubule reaches the sides of the acetabulum it is 

 directed forward. In the very young cercaria it has a serpentine 

 course. This tendency becomes progressively more pronounced 

 as the larva develops, until in the mature cercaria it consists of a 

 spiral of about six definite loops. At the place where the lateral 

 collecting tubule reaches the eye-spot it reflexes outward and 

 backward. Its course may be traced to the region of the bladder 

 where it runs into the acetabulum. The posterior limit of the 



