186 



s. GOTO. 



This is caused by the. opening at this point of numerous flask-shaped 

 unicellular glands (shg), fjie shell-glands. The wall of the uterus 

 proper (Ootyp, Fig. 24) is lined by a distinct epithelium, whose 

 cells contain each a round nucleus projecting into the internal cavity. 

 The protoplasm is granular and no cell-boundaries are to be seen. 

 The epithelium sits on a distinct basement membrane and is destitute 

 of cilia. The remainder of the uterus (Eiergang) is provided with a 

 similar wall (Fig. 23), with the nuclei, however, more separated 

 from one another. Here, as already stated, the wall is beset with 

 long cilia. 



The vitelline body is an extensive lobed body (Fig. 2, vb) situat- 

 ed exclusively in the anterior half of the body, all around the 

 intestine both on its dorsal and ventral sides. In specimens in wdiich 

 reproduction is going on, each lobe is seen, when fresh, to contain a 

 dark granular mass. Sections (Fig. 19) shew that each lobe consists 

 of a number of cells containing numerous yellowish granules, 

 each with a nucleus and a nucleolus in the centre, and a thin cell- 

 wall. These are the ripe yolk-cells, îmd when freed take up a globular 

 form. In the peri|)heral portion iu*e seen smaller cells wdth a deeply 

 stained protoplasm, a nucleus and a nucleolus. The protoplasm is 

 homogeneous, finely or coarsely granular according to their different 

 stages of development. They are the young yolk-cells ; and there are 

 also to be observed cells intermediate between these two kinds — cells 

 one half of whose content has already been changed into yellowish 

 yolk-granules while the other half still consists of granular protoplasm. 

 During the winter months, the yolk-cells present a quite different 

 appearance (Fig. 20). Tliey are then scarcely to be distinguished 

 from the cells of the mesenchyma of certain species of Microcotyle. 

 They are then of a polygonal form, with a distinct cell- wall, a round 

 nucleus and nucleolus, and a granular protoplasm which stains very 



