174 Mr. Griffith on the Ovulum of tantalum, 



assumable to be pollen tubes, adhere most intimately to the apices of the sacs ; 

 generally one, sometimes more, will be found adhering. By varying the modes 

 of examination, I acquired the conviction that the pollen tube passes down 

 between the connivent teeth and enters the apex of the sac, when it expands 

 into the vesicle just mentioned. (Tab. XVII. fig. 4, and especially fig. 6.) 



This vesicle contains grumous molecular matter. On reaching its full 

 amount of expansion, which is considerable, the free end will be found in 

 direct communication with the coagulum, which forms an uninterrupted line 

 as far as the convex septum ; its upper end tapers into a neck, which corre- 

 sponds with the axis of the teeth and with its sides ; but to an unequal and 

 incomplete extent, dense grumous matter will be seen to be in contact. 



The coagulation of the contents is universal ; it is most distinct in those 

 that are to be abortive, in which it forms a flattened club-shaped line, 

 studded here and there with a few large granules, almost all of which do not 

 fail to disappear from the fertilized one. 



The abortive tubes undergo no further change ; the fertilized ones soon 

 present cellularity of the bulb and nucleary aggregation of the contents of 

 the neck, which subsequently also becomes cellular. (Tab. XVII. fig. 7.) 



The cellularity of the bulb is always in advance, and even when it has at- 

 tained a considerable size, the upper or tubular part presents only the first 

 steps to cellularity, aggregation into nuclei, and then the division of these. 

 The direction of the cellularity in this part appears irregular, but generally I 

 have observed it to be most developed towards the vesicle and towards the 

 bulb, and least in the intermediate part. If the bulb be examined about this 

 period, it will be found that the cells have, as it were, extended downwards 

 over that part of the sac beneath the septum, and that the whole of the bull, 

 and tubular part is easily separable from this, which, when detached, presents 

 an entire globular head strikingly similar to that of Oyris 



The cellularity continuing to increase, finally occupies the whole sac above 

 the hue of separatum, and in the meantime the lower free end of the vesicle 

 wi 1 be found to present traces of internal subdivision, preceded by the aggre- 

 gation of* contents into nuclei. (Tab. XVII. fig. 9 ; ; The next process con- 



Sn m oH 7 "T f CGl,S fr ° m US l ° Wer *" end > and *™ these 

 again other cells are developed, forming a cylindrical mass of lax nucleary 



