THE PKINCIPLE OF COHESION. 



71 



appeared, d represents a section of two-thirds of the height 

 of the inferior ovary; but now the fibre-vascular cylinder 

 is dissociated, and forms fifteen separate cords — two being 

 marginal to each placenta and one belonging to each septum. 

 As the cords have their spiral vessels reversed in position, 

 i.e. facing outwards and not inwards towards the centre, 

 their axial character has ceased.* 



ng. IB.— Oimponula medium (after Van Tleghcm). 



The rule appears to me to be that as soon as, or even 

 before the level of the insertion of the ovules is reached, the 

 internal position of the tracheae is abandoned. This is the 

 case with Lychnis. 



In some cases there is an apparently axial formation, 



* I do not find that matters can be really expressed quite so "diagram- 

 matically " as, e.g., in his figure d ; for Van Tieghem does not pay mnch 

 attention to the central wnd scattered positiona of the tracJiew, which I 

 take to be qnite aa significant as their outward orientation ; for as the 

 ovules are approached they become dispersed, thoagh a medulla remains. 



