KAri'LKSlA AKNOi.Dl. 107 



when tlicy again become active and increase in size until 

 they once more com[)letely cover it. 



AVhile the development, as I liave liere described it, of 

 the nucleus and its integument in llaj/lcsia is going on, 

 another change is at the same time gradually taking place, 

 namely, at first a slight bending, which at last ends in a 

 coniplete inversion, in the direction of the nucleus and its 

 integument in regard to the placenta, with which, in this 

 advanced stage, tlie perforated apex of the latter is nearly 

 or absolutely in contact. 



In this change of direction, the ovulum of Ihijllcmi 

 resend)les that of the far greater part of Phienogamous 

 plants : the change, however, is effected in a w^ay which is 

 much less connnoii, the curvature in Rajllesia taking })lace 

 solely in the npj)er part of the funiculus, the direction of the 

 inverted ovulum being parallel with, but distinct from, the 

 portion below the curvature ; whereas in Phsenogamous 

 ])lants generally, the curvature is produced in that part of 

 the funiculus which is connate with the testa or outer 

 integument. For this difference, a reason, perhaps, may 

 be assigned ; the integument which generally forms the 

 testa or outer coat being in Ilafflesia entirely wanting, or 

 only indicated ])y the remarkable dilatation of the apex of 

 the funiculus.^ 



In the more essential points of structure, the ovula of 

 llf/diiora and Cijtunis agree with that of HaJ/lesia. They 

 ditl'er, however, in both these genera in retaining their 

 original direction. 



In Hydnora I have ascertained the perforation of the single 

 hitegument and the position of the included nucleus, :^-ri 

 but the very earliest stages I have not yet distinctly seen ; 

 while in Ci/tinus, in addition to the coat analogous to that 

 of IxajjlcHia and Jl)/dnora, a two-lobed or bipartite mem- 

 brane is observable. 



Of these three genera, I have hitiierto observed the pollen 



> The. earlier production ol' the inner of llie two coats generally present in the 

 ovula of ^lueno^'an)()Us |)lants, and vhe absence of the outer in this and several 

 other cases, will probably be considered a valid objection to the tcrminolo<:y ol 

 M.Mirbcl. 



