v PHYLUM PLATYHELMINTHES 243 



.-.unified tulx-s which occupy the middle part of the body, one 

 situated behind the other. From each testis there runs forwards 

 a duct, the vas deferens, the two vasa deferentia (v.d.) opening 

 anteriorly into an elongated sac, the vesicula seminalis (v.s.) from 

 which a narrow tube— the ejaculatory duct (Fig. 189, eld.)— leads 

 to the male aperture at the ex- 

 tremity of the cirrus. The female 

 part of the reproductive apparatus 

 consists of a single ovary (ger- 

 marium), an oviduct, a uterus, an 

 ootypc, vitelline glands, vitelline ducts, 

 and shell-glands. The germarium 

 (Fig. 188, ov.) is a branched tube 

 situated on the right-hand side in 

 front of the testes; the branches 

 open into a common narrow tube, 

 the oviduct (od.). The vitelline 

 glands (vit.) consist of very nu- 

 merous, minute, rounded follicles, 

 which occupy a considerable zone in 

 the lateral regions of the body. On 

 each side are two large ducts, 

 anterior and posterior, uniting to 

 form a single main lateral duct, 

 right or left ; and these run nearly 

 transversely inwards to open into a 



ZcfrT^jf TT^ u Fr ° m this a sin S Ie media » ^elline 

 duct runs backwards for a short distance to join the oviduct 



th at tefS F gr °T d a , maSS ° f UnicelIular shelT^ands 

 (sh. gl.), each of which is produced into a narrow process or duct 



opening in to the end of the oviduct in the region of th flatter to 

 fluted t e ut rm f^ L S ap f liGd - • The Ute ™^ » a tide c^ 



vt£e&lTf X th6 UD T ° f thG ° vidllCt and median 

 Whpn tL ' fuV* ° penS close t0 the base of the cirrus 



doaea i s fo3 ™ ™ thdr »" "k* sma11 ^ity, the genital atrium* 



and femat dnl T° n 'V^ eXternal a P ertures of b °th male 

 and female ducts. A canal, termed the canal of Laurer leads 

 from the junction of the oviduct and median vitelline duct to 

 open externally on the dorsal surface vitelline duct to 



rou^dld 1 ^ 111611 *'"^^-/^ 111 ° n im Pregnation becomes sur- 



XtlanSs ItXnt Vltelhne T^ ° r y° lk derived from ^e 

 on v2 «. then becomes enclosed, while passing through the 



ootype m a chitinous shell, the substance of which is usuallv said 

 to be derived from the shell-glands The completed egg remaps 



dealing with the general organisation? ^ ** "*"*"* t0 m the section 



R 2 



Fig. 189.— Fasciola hepatica. Ter- 

 minal part of the reproductive' 

 apparatus, ej. ejaculatory duct • /. 

 female aperture; g. unicellular 

 glands ; od. terminal part of oviduct ; 

 _ p. cirrus; ps. cirrus-sheath; «' 

 sucker; v. d. vasa deferentia; v i 

 .vesicula seminalis. (After Sommer ) 



