97 



The hermaphrodite reproductive system is repeated in each 

 proglottis. The male organs are formed first. The male 

 and female sexual orifices open together into a genital 

 atrium or external opening which is situated (in rough 

 alternation) on the right or on the left side of the pro- 

 glottis. 



Describe the Structure of a Mature Proglottis. 



The outer cortex consists of thick cuticle and longitudinal 

 muscles. Underlying this is a layer of circular muscles 

 surrounding the inner parenchyma in which the repro- 

 ductive organs are embedded. 



At each side of the proglottis are the portions of the 

 longitudinal nerves and the excretory canals. Connecting 

 the latter, is a transverse vessel, across the posterior end. 

 The greater part (of the mature proglottis) is occupied by 

 the fully-developed hermaphrodite reproductive system. 

 The male organs, small pear-shaped testes, are numerous 

 throughout, but more towards the surface which is re- 

 garded as dorsal. The ducts (vasa efferentia) unite and lead 

 into the convoluted male duct or vas deferens which opens 

 into the external genital atrium, on the right or the left 

 side. The end of the vas deferens is surrounded by a 

 protrusible cirrus or penis. The female organs are in 

 the compact form of a paired ovary or germarium, lying 

 in the posterior half of the proglottis and towards the 

 surface regarded as ventral. The female orifice is be- 

 side the male opening ; and leading from it is the vagina, 

 which ends in a dilatation, the receptaculum seminis. 

 A short continuation from this joins the oviduct from the 

 ovaries, and the continuation of the oviduct from that 

 junction is called the fertilisation canal (within which the 

 eggs are fertilised) ; it receives the vitelline duct from the 

 yolk gland (which supplies the food yolk for the nourish- 

 ment of the developing embryo), also numerous ducts from 

 the shell gland (the secretion of which forms the egg 

 "shell"); and it is further continued as the uterine canal 

 which enters the expansive and blind uterus proper. 



