190 M7\ Griffith on the Ovulum o/'Santalura, 



growth of the cells to it ; neither would such an occurrence, perhaps, be con- 

 sistent with the situation at which the embryo subsequently makes its appear- 

 ance. In the barren sacs, appearances may often be seen of a sort of tubular 

 communication between these remote points ; but these are always partial, 

 and always least evident close to the vesicle. This occurrence of the cellu- 

 larity so remote from the end of the boyau is obviously analogous to what 

 occurs in Osyris, if the situation of the embryo be kept in view, and perhaps 

 may be taken into consideration in explanation of the origin of the first similar 

 cellular tissue in that plant ; and it appears to me to show that the sac in 

 question is possessed, at least in certain instances, of higher functions than 

 M. Schleiden seems disposed to allow. 



Another remarkable anomaly in Santalum consists in the subsequent sepa- 

 ration of the sac along the line of the septum, for such I believe to be the part 

 at which the solution of continuity takes place. My observations on this 

 point, and indeed as regards the actual structure of the bulb, when cellular, 

 are by no means so decisive as I could have wished ; this will be evident 

 from inspection of the drawings. In general, appearances are perhaps in 

 favour of the supposition of the formation of a globular cell from the septum, 

 which cell forms the head of the lower part of the sac ; if this is the case, it 

 becomes completely identified with those parts of the septum from which it is 

 supposed to originate. 



This extraordinary separation is not the only manner in which a striking 

 transition to the form of sac in Osyris is manifested ; for the original tubular 

 sac will at a certain, and not very late period, be found entirely incorporated 

 with the cells, being divided into as many integral parts as there have been 

 cells developed within it. This is remarkably different from what takes place 

 in some other membranous embryo-sacs, in which, even in the ripe seed, the 

 membrane continues to exist in its original entire state, forming a hyaline 

 edge round the albumen. 



At this period the similarity between Santalum and Osyris is highly 

 remarkable, differing so much as they did in original structure; and were 

 it not for the obvious continuity of the whole of the embryo-sac of Santa- 

 lum at an earlier period, I should be tempted to consider the part above the 

 septum to be of an intermediate nature, analogous to the pi-ocess of the 



