Osyris, Loranthus and Viscum. 189 



the grumous matter. After fecundation has occurred the coaguhim is coloured 

 fuscous, the violet tinge occasionally, but not always, affecting such of the 

 granules as have not disappeared. 



The changes in the contents of the sacs consequent on fecundation are not 

 marked mOsyris, or in that portion of the sac of Santalum below the septum. 

 Above this, as I have mentioned, the first change consists in a sort of coagu- 

 lation, which is very evident in those determined to be barren, in which they 

 will be found to be changed into a grumous mass, in apposition above by a 

 broad base with the free end of the vesicle, tapering thence into a flat, often 

 undulated line, communicating with the vesicle and with the summit of the 

 convex septum ; the line of communication being often interrupted towards 

 this point. To the broad part of this coagulum a few of the largest granules 

 will generally be found adhering. 



The coagulation is much less marked in the fertilized sacs, and is chiefly 

 observable from a tendency to the aggregation of the grumous matter into 

 masses, accompanied by the complete disappearance of the larger granules. 

 This aggregation of grumous or minutely molecular matter seems to me to 

 constitute the prelude to the appearance of cellularity. I have been particu- 

 larly struck with it in following the development of the pollen of certain 

 plants, with which the development of the cells of the young seed of Santa- 

 lum would appear to present curious analogies. (Vide Tab. XVII. fig. 7-) 



The cellularity is first manifest in the bulb above the septum, in which 

 situation the nucleary aggregation is of earlier occurrence and more decided 

 appearance. The strong tendency to the first appearance of the cellular tissue 

 at the part alluded to, is shown by the occasional occurrence of a cellular 

 bulb and an abortive tubular portion. The last direction in which it becomes 

 evident is in the intermediate part of the tube, but there is perhaps some little 

 variation in this respect. 



It is in the appearance of the cellularity at such a comparatively great 

 distance from the vesicle that one of the principal anomalies of Santalum 

 appears to me to consist. On this singular point I can offer no explanation, 

 the limits of the vesicle being distinct some time after the commencement of 

 the cellularity of the bulb. I have not been able to ascertain any tendency to 

 such elongation of the vesicle downwards as would enable me to refer the 



2 c 2 



