316 



THE ANATOMY OF CESTODES. 



same height, but does not, like the ovaries, approach the ventral, 

 but the dorsal surface. 



Lastly, as regards the uterus, it is at first, in the Tgeniadae, a 

 simple and straight canal, which, according to the form of the body, 

 runs in a transverse or perpendicular direction, and in the latter case 

 its posterior end (or its middle, as in Tcenia perfoliata, Fig. 162, B) 

 is connected with the vaginal canal. Like the other portions of the 

 female apparatus, it consists of a structureless, expansible, and elastic 

 membrane, whose external surface exhibits the repeatedly mentioned 

 but here specially abundant accumulated cells. Since there is also 

 no appearance of any special muscular covering in the uterus, the 

 expulsion of the eggs through the previously formed rupture must, 

 of course, be effected by the pressure of the muscles of the body. 



But afterwards, when the eggs are transferred into it, and accumu- 

 late in it in ever larger numbers, and of increasing size during the 



FIG. 167. Proglottides of Tcenia nana at maturity ( x 100). 



FIG. 168. Mature joint of Tcenia perfoliata with uterus ( x 10). 



development of the embryo, this primitive form of the uterus undergoes 

 a continuous and often very striking change. In some cases it consists 



of a simple enlargement, often so ex- 

 tensive that the original linear tube 

 becomes a bulging sac (Fig. 167), and 

 in other cases lateral processes, vary- 

 ing in number and width (Fig. 168), 

 are formed, which ultimately turn into 

 slender and often branching twigs (Fig. 

 169). But such differences, however 

 highly characteristic of the different 

 groups and species, can only be shortly 

 noted. Therefore I shall only observe 

 that in some cases the uterus even 

 breaks up into many round vesicles, containing a larger or smaller 



FIG. 169. Joint of T. saginata 



