T.ENIA SAGINATA GOEZE 77 



the receptaculum seminis. Immediately beyond this the vagina 

 receives the oviduct and proceeds then as the so-called fer- 

 tilization canal to the ootype where it unites with the yolk duct 

 and the uterus. The two ovaries although having the appearance 

 of more or less round bodies, are in reality composed of a number 

 of tubular follicles. Their ducts unite in the median line of the 

 proglottis and form a short common oviduct which, as already 

 stated, opens into the vagina behind the receptacle for the 

 sperm. The yolk gland is single, situated close to the posterior 

 end of the proglottis. The yolk duct is short, straight and opens 

 into the fertilization canal in the ootype in the same place with 

 the uterus. The uterus appears as a blind tube of considerable 

 size running forward almost to the anterior edge of the proglottis. 

 In maturing proglottids this tube is simple, but under the pres- 

 sure of eggs it begins to develop branches and in the rearmost 

 proglottids occupies almost the entire space. There are then 

 from twenty to thirty-five branches on each side of the median 

 canal of the uterus. The Mehlis' gland or ootype has an almost 

 circular shape and consists of numerous glands each opening 

 separately into the fertilization canal at its place of union with 

 the uterus and yolk duct. 



Self-fertilization is usual, but cross-fertilization occurs. The 

 sperm is stored in the receptacle. The eggs are fertilized in the 

 fertilization canal, and on being supplied with yolk and sur- 

 rounded with a shell pass into the uterus. They reach the out- 

 side through a disintegration of the tissues or are swallowed with 

 the entire proglottis. The development is combined with a 

 metamorphosis and a change of hosts, the intermediary host 

 being cattle. The first larval stage is known as an oncosphcera 

 which on reaching the muscles (or sometimes internal organs) 

 becomes transformed into a cysticercus. 



Instructions 



i. Examine under dissecting microscope the prepared slide 

 of a mature proglottis. It shows the longitudinal and transverse 



