AET. 20. TWO NEW INTESTINAL. TREMATODES TUBANGUI. 5 



both measured at the anterior third of the body. The ventral folds 

 (figs. 2 B and 4 C), which originate on either side of the oral sucker, 

 meet at about the level of the beginning of the posterior third of the 

 body and form the borders of a large cavity occupied by the ex- 

 tensively-developed clinging plug (figs. 2 A, B). The clinging plug 

 (" Haftapparat," " Zapfenapparat") is smooth and dome-shaped 

 externally and provided with a broad base reaching from the ace- 

 tabulmn to a point slightly behind the posterior limit of the ventral 

 folds. In some specimens it is confined within the cavity formed 

 by the folds, but often it bulges out anteriorly in such a manner 

 as to force back and overlie in ventral view both the pharynx and 

 oral sucker (fig. 2 A). In its anterior end, in front of the vitellaria, 

 are found numerous unicellular glands, probably representing the 

 so called " Haftapparatdrlisen." 



The oral sucker, 0.10 to 0.13 mm. long and 0. 18 to 0.19 mm. wide, 

 is terminal or antero-dorsal, depending upon the position of the 

 clinging plug. It is immediately followed by a globular pharynx 

 0.10 to 0.13 mm. long and 0.13 to 0.14 mm. wide. The acetabulum 

 (fig. 4 B), 0.10 to 0.11 mm. in diameter, is weakly developed and 

 hidden by the clinging plug. It is located in the anterior third of 

 the body, a short distance behind the pharynx, at the angle formed 

 by the base of the clinging plug with the anterior region of the body. 

 Its position suggests that it may serve with the ventral folds and 

 clinging plug as an attaching organ. No esophagus being present, 

 the simple intestinal branches arise directly from the pharynx; at 

 first very narrow, they are much wider posteriorly. Their termina- 

 tions, which are near the posterior end of the body, are visible, but 

 the greater parts of the intestinal branches are hidden between the 

 testes and vitellaria. 



The testes are large, smooth, oval in shape, elongated antero- 

 posteriorly and placed one behind the other; their point of contact 

 with each other is about half-way between the anterior and posterior 

 ends of the body. The anterior testis is somewhat smaller and is 

 more inclined ventrally, its anterior extremity extending into the 

 substance of the clinging plug (figs. 4 A, B). It measures 0.49 to 

 0.52 mm. long and 0.33 to 0.45 mm. wide and, like the posterior testis, 

 it varies in thickness from 0.30 to 0.40 mm. The posterior testis 

 is 0,65 to 0.81 mm. long by 0.36 to 0.38 mm. wide; approximately 

 one-half of its length lies anterior of the posterior limits of the 

 ventral folds and the other half posterior. The vasa efferentia (fig. 

 4 A) originate from the mid- ventral borders of the testes; the com- 

 mon duct arising from their union, or the vas deferens, enters thi 

 cirrus sac and is enlarged to form the vesicula seminalis. The cirrus 

 sac is comparatively very much elongated, lying ventral to the two 

 testes toward the right or left side (amphitypy) and measuring 0.70 



