GENUS OF PARASITIC GASTROPODS. IO5 



large cavity, ventral to the body proper, that communicates with 

 the exterior. The second pursues a course anteriorly in the 

 pseudo-pallium and disappears from view among the large ova. 

 The third, also in the pseudo-pallium, makes its way backward 

 for a considerable distance but finally vanishes in several small 

 muscle bundles. 



Together with Entoconcha and Enteroxenos this species is 

 monoecious and the ovary and testis are separate and distinct. 

 The testis occupies a position lateral and ventral to the stomach 

 about opposite the level of the pharynx, and is bilaterally sym- 

 metrical and gives evidence of being a paired organ. In the 

 region concealed by the liver in Fig. i. PI. I., the organ is con- 

 tinuous across the mid line ; but anterior to this point the 

 unpaired division develops an extensive anteriorly directed pouch 

 on each side of the stomach. The gland is in an immature con- 

 dition, containing many spermatogonia but no later stages. 

 Behind the unpaired section a duct of very large caliber arises, 

 on each side of the mid line, with thin walls and a glandular, 

 apparently ciliated, low ridge on its inner face. In this condi- 

 tion it continues to a point opposite the middle of the kidney 

 where it contracts abruptly to a slender, thicker walled tube 

 which is directed ventrally to open into the narrow slit-like space 

 between the body and some of the kidney lobes. 



The ovary is confined to the large fold enveloping the body, 

 practically all of the space unoccupied by the liver being filled 

 with large ova. These are suspended, almost precisely as in the 

 chitons (see Haller's Fig. 328, Lang's " Lehrbuch," p. 366), in 

 slender sacs, outpouchings of the germinal epithelium, and in a 

 completed condition are surrounded by a follicle. No definite 

 oviducts are present, the ova probably escaping by means of 

 ruptures in the wall adjacent to the body proper. 



The ova, fertilized either in or out of the body, may readily 

 escape from the animal and from the host and doubtless in the 

 free-swimming stage make their way to another host into which 

 they burrow and take up their final position. The changes that 

 ensue are wholly unknown but it is evident that the fold or 

 pseudo-pallium, in this species at least, is not a portion of the 

 foot. As may be seen in Fig. i it arises as a duplicature of the 



