STÜDTRS OX THE EOTOPAEASTTIC TItEMATODES OF JAP AN. 10.5 



it.self at tlic middle, so as to form a loop across the length of the 

 body ; but in tliis g-enns the pr(^ximal end of the ovary, /. i\, the zone 

 of fonnation, is enlarged info a globular shape, while the remaining 

 portion is throughout of an almost uniform tliiekneAS so th;it AVierze- 

 jski" was led to call this ])ortion the o\'idu('t (Eiluitei-). Ihit th:it 

 it corresponds in reality to the zone of gi-owth is ver}' clear fi'om 

 a. comparative study of the ovary in different genera. Wh:it 

 seems to l)e very peculiar is thiit the closed end of the loo]) whicli 

 the ovary foians in this genus enciiclcs the intestine (IM. XIX, 

 fig. 1). This is also the case in 'Monocotijh' ; but in this genus the 

 formative zone passes gradually into the zone of growth, aiid the whole 

 ovary makes an a(hlifion:d hirge winding or two (PI. X\'ir, fig. 1). 



Tn T)icIlilnj)lioni the form of the (^vary varies mu(h in different 

 species. The simplest form is found in DicUd. eloiKiahi, in Avhich a 

 long cylindrical ovary is twice bent on itself so that each half is horse- 

 shoe shaped (1?1. X, fig. 9). Tn Diclid. .sr.s'.s/7/.s' also, each lialf of the ovary 

 is bent on itself so that tlie Avhole looks somewhat like flie letter W; 

 but the four :uans of the W are closely ap|)lied to each other, and the 

 terminal ])orfion, /. ('., that which gives rise to the oviduct is very 

 much l.'ii'ger tli:iii the t)fher three, and contains a ca\if\' filled with 

 a s])arselv fila'ous comiccfive tissue (PI. X. fig. o). \\\ ]>icli:L 

 t<'lro(Jonis^ again, the somewhat commn-sliaped ovarv makes a spiral 

 winding to one side at its middle, so that the whole looks some- 

 what like the embryo of the chick in profile, with its large heart 

 protruding from its ventral side at n short distance from the head 

 (PI. X, fig. 1); the head of the embry(^ answering to the oviduct 

 end of the ovarv and the tail end to the formative zone. Tu ( hiclioco- 

 tijJc the zone of formation occupies .about one-fifth of the wliole length 



1). Wierzejski — Zur Kenntniss des Baues von Calicotyle Kroyeri. Zeitschr. f. wiss. 

 Zoolog., Bd. 29, 1877. p. 557. 



