980 



On the subject of Viscinn, Mr. GrifRtli says "the modifications are 

 two ; in the one an evident cavity exists in the ovarium, and the 

 ovulum appears to be reduced to an erabryonary sac, hanging from the 

 side of the base of a nipple-shaped or conical placenta ; in the other 

 the ovulum is reduced to an embryonary sac, but this is erect, and has 

 no such obviously distinct point of origin as in the first. In both the 

 albumen has no other proper covering than the incorporated embry- 

 onary sac ; and, at least in the last, the embryo appears to be a direct 

 transformation of the pollinic vesicle." 



In Santalum, and also in Osyris, " the ovulum is reduced to a 

 nucleus and an embryonary sac, prolonged beyond both the apex and 

 base of the nucleus ; the albumen and embryo are developed in the 

 parts above the septum (in the exserted portion of the sac), the parts 

 below and the nucleus remaining unchanged. The seed has no ac- 

 tual proper covering, and no other theoretical covering than the incor- 

 porated upper separable parts of the embryo sac." 



In Loranthus " each ovulum appears to be reduced to an embryo- 

 nary sac, the albumen is developed either partly within the sac, or 

 entirely or almost entirely without it. The embryo is a growth from 

 the ends of the continuations of the pollen-tubes outside the anterior 

 ends of the embryo-sacs, and is in one modification (L. globosus) up 

 to a certain period exterior even to the albumen. In L. bicolor the 

 albumen has no proper tegument; in L. globosus it may be supposed 

 to have a partial one in the incorporated albuminous part of the em- 

 bryo-sac." 



In his summary of the novel points of structure, &c., indicated in 

 his paper, he mentions {inter alia) 1st. The longitudinal percursion 

 of the embryo-sac by the pollen-tubes. 2nd. The formation of the 

 albumen either only partially within the embryo-sac, or almost entire- 

 ly, if not quite so, without it. 3rd. The confluence of the albumina 

 of several sacks into one albumen. 4th. The growth of the embryo- 

 nic tissues from the continuations of the pollen-tubes outside the em- 

 bryo-sac. 5th. The possibility of one embryo-sac resulting from a 

 combination of several pollen-tubes, and of its becoming anterior to 

 the albumen, although it may have been for some time entirely exte- 

 rior to it. 



Now, it seems impossible to reconcile, in the same example, the 

 first point with the fourth (which indeed appears to have been re- 

 tracted as an error in the note of November 19, 1844) ; indeed, the 

 general tendency of Mr. Griflith's remarks (if we except his fifth point) 

 is to create the impression that he considered the embryo-sac to be 



