452 STRUCTURE OF THE UNIMPREGNATED OVULUM. 



markable germination, as observed and figured in Nymphaea 

 and Nupliar by.Tittmann.^ 



In support of this explanation, ^A'llicll differs from all 

 those yet given, 1 may here advert to an observation pub- 

 lished many years ago, though it seems to have escaped 

 every author wlio has since written on the subject, namely, 

 that l)efore the maturity of the seed in Nymph seacege, the 

 sacculus contains along with the embryo a (pidpy or semi- 

 fluid) substance, which I then called Vitellus, applying 

 at that time this name to every Ijody interposed between 

 the albumen and embryo.^ The opinion receives some 

 confirmation also from the existence of an extremely fine 

 filament, hitherto overlooked, which, originating from the 

 centre of the lower surface of the sacculus, and passing 

 through the hollow axis of the Albumen, probably connects 

 this coat of the Embryo in an early stage with the base of 

 the nucleus. 



5541 The same explanation of structure applies to the seeds 

 of Piperacea3 and Saururus ; and other instances occur of 

 the persistence either of the membrane or of the substance 

 of the amnios in the ripe seed. 



It may be concluded from the whole account which I 

 have given of the structure of the ovulum, that the more 

 important changes consequent to real, or even to spurious 

 fecundation, must take place within the nucleus ; and that 

 the albumen, properly so called, may be formed either by a 

 deposition or secretion of granidar matter in the utriculi of 

 the amnios, or in those of the nucleus itself, or lastly, that 

 two substances having these distinct origins, and very 

 different textures, may coexist in the ripe seed, as is pro- 

 bably the case in Scitaminese. 



On the subject of the ovulum, as contained in an ova- 

 rium, I shall at present make but one other remark, which 

 forms a necessary introduction to the observations that 

 follow. 



' Keinumg der Pflanzen, p. 19 et 27, tab. 3 et 4. 

 - Prodr. 'Flor. Nov. IIoll. i, p. 30G. 



