^0. 3 manter: a new genus of distomes 17 



The excretory system is like that of Apocreadium wexicanum. 

 The narrow excretory vesicle gives rise near the posterior testis to 2 

 pairs of anteriorly directed tubules, one pair larger than the other. 

 Both pairs extend foru^ard at least as far as the acetabulum but 

 only one pair seems to reach as far as the oral sucker. From the 

 common stem of each pair near the median vesicle a single sinuous 

 tubule passes posteriorly on each side. 



The lymph vessels are well developed. They are considerably 

 branched in the posterior half of the body as In A. mexicanum. The 

 branches run almost parallel with the stems, diverging gradually 

 toward the body surface. They are not swollen at their tips as are 

 such branches in A. rnexicamnn. The lymph vessels of the forebody 

 also branch but here the branches are shorter and may extend in 

 any direction. Because of the courses taken by the branches, the 

 number of main stems of the lymph system is very difficult to deter- 

 mine. For some distance posterior to the testes there seem to be 

 4 pairs of longitudinal tubes, although 2 pairs extend farther back 

 than the others. In the region of the acetabulum there seem to be 

 2 pairs. An accurate count was not possible in the forebody. In most 

 specimens one pair extended into the preoral lobe. Evidently the 

 lymph system Is very similar to that of A. mexicanum. 



Lymphocytes or at least large cells of some kind (plate 2, fig. 

 7) are not infrequent within the lymph vessels. These cells seem to 

 have been amoeboid. They measure 14 to 19 /u, in diameter which 

 Is as great as the diameter of most of the lymph vessels. The cyto- 

 plasm of these cells Is finely granular, the nucleus staining very 

 deeply, much more deeply than those of other cells. 



SPECIFIC DIAGNOSIS OF Apocreadium longisinosum 



(Measurements in mms.) 



Body tapering toward each end, pointed at posterior end, widest 

 at midbody, 6.57 to 9.65 by 1.552 to 2.403, In Hfe orange-yellow In 

 color. Oral sucker 0.375 to 0.532 In diameter; acetabulum }i from 

 anterior end, 0.675 to 0.885 In diameter, with longitudinal aperture. 

 Genital pore median close in front of acetabulum. Short prepharynx, 

 pharynx 0.210 to 0.292 (length) by 0.225 to 0.315 (width), anterior 

 third slightly modified; esophagus short; bifurcation about midway 

 between suckers; ceca narrow extending to near posterior end. 

 Testes tandem, close together, slightly lobed, squarish, just poster- 



