434 



DR. F. E. BEDDARD ON 



the middle of the proglottid and on a level with the cirrus-sac. 

 It forms a nearly straight line about the middle of the proglottid, 

 wider in the middle of its length and tapering off to the side of 

 the proglottid remote from the cirrus-sac, in which direction it 

 does not reach the lateral water-vascular tube. At the other end 

 the growing uterus is limited by the cirrus-sac and the coil of the 

 vas deferens. In the lateral, most immature part of the uterus 

 that oi'gan appears to be formed by only a very slight modification 

 of the medullary tissue. There is simply an increase in the 

 number of the nuclei, which are thus closer together and become 

 more conspicuous. 



Text-figure 3. 



vf. 



Horizontal section throngh immature proglottid, to illustrate earliest appearance 

 of uterus {ut^. ov. Ovea-y. 



In the more central parts of the uterus at this stage, which, as 

 already said, is wider, the nuclei are more abundant, both actually 

 and relatively. Between them cavities appear, all of them small 

 but of varying sizes ; the dimensions of some coincide very closely 

 with the meshwork of the general medullary parenchyma. The 

 nuclei, at least in many cases, are arranged round these spaces in 

 a regular fashion and thus constitute a lining epithelium to these 

 uterine cavities.. The several cavities are separate from each other 

 in this early formed uterus. Fuhrmann * has observed the same 

 mode of origin of the uterus of Chapmania tauricollis, and 

 remarks : " Anfangs erscheint der Uterus gekammert." 



In later stages there is a confluence of these ca.vities, and in 

 the fully developed uterus such as is represented in text-fig. 4, 

 the uterus appears to consist of a larger central cavity which is 

 prolonged in all directions through the medullary parenchyma 

 into outgrowths. I am disposed to think that these latter inter- 

 communicate and form a network. In horizontal sections near 

 to the dorsal and ventral surfaces of the uterus the retiform 

 appearance is very strikingly manifested. In transverse sections 



* Rev. Suisse Zool. iv. 1896, p. 121. 



