AVIAN CESTODES. 865 



It will also be seen, on an inspection of that figure, that the 

 fully grown ova are largely grouped together in cavities, and that 

 the ovary is more or less hollow. I am not, however, disposed 

 to think that this fact has any morphological significance. Two 

 interpretations are, of course, conceivable. Firstly, that the 

 space is coelomic, the eggs having been freed from its walls into 

 its cavity. The occurrence of a similar cavity in other tape- 

 worms may perhaps be an argument in favour of this view, which 

 is by no means impossible (and, indeed, has been theoretically 

 demanded by Bergh and others) ; yet I am disposed to regard the 



Text-fig. 143. 



spa 



■ \ 



, •'\ 



e.s. 

 1 



iv. 



\ 



y 



'>^ 



f 



\ ( "-?- 



.** ^' 





Part of a horizontal section through a j)rog]ottid of JStigonodceum cedicnemi. 



e.s. Egg-sacs. l.v. Ventral water-vascular tube. sp.d. A part of coil of sperm-duct 

 lying in front of ovary, t. Testes, t.v. Transverse water-vascular tube. 

 V. Vitelline gland ; in front of this is the ovary, of which the darkly stained 

 mature ova are partly received within cavities of the parenchyma. 



cavities as merely due to shrinkage. These hollows might also 

 be considered as the commencement of the uterus. The position, 

 however, woulel be rather abnormal ; and, moreover, as again 

 is insisted upon later in this paper, ripe ova are already scattered 

 through the parenchyma, the cavities surrounding which can 

 therefore have nothing to do with the cavity in the ovary, what- 

 ever may be its nature. In younger stages than that which has 

 just been described the ovary forms a quite solid mass. Later 

 on it seems to disappear as a definite structure. 



