14-i TRANSACTIONS AND PROCEEDINGS OF THE [Sess. lv. 



different sporocytes, and being brought into close contact by 

 their mode of formation, conjugate, and thus give rise to a 

 fertilised cell, the endosperm-cell, while the three remaining 

 spores form the antipodal cells. These three antipodal cells 

 should then, according to reasons just stated, namely, being 

 nourished better tlian the remaining five spores, preserve 

 their true spore-cliaracter longest, and tliis really seems to be 

 the case in plants like Zca metis, Coix lacrijma, Fanicicm crus- 

 galli, Salvia pratensis, and some scrophularineous plants 

 (Westermeyer), where the antipodal cells proliferate, and 

 form the primordial endosperm, which, if my interpretation 

 be correct, would correspond to prothalli formed by the 

 antipodal spores, when, due to the fertilisation of the egg- 

 cell, more nourishment is brought to the ovule. The objec- 

 tions raised by Ward against the interpretation of the eiglit 

 structures within the embryo-sac as spores are shortly these : 

 It is stated that one would expect to find in angiospermous 

 ovules the process of reduction of the sexual generation 

 (oophyte) carried on somewiiat as in ( iymnosperms, but to a 

 further extent ; and that ascending from the lower Crypto- 

 gams to the Conifene the male prothallus is found to suffer a 

 greater reduction than the female ])r()Lliallus. As further in 

 Conifene the pollen-grain contains several prothallus-cells, 

 w'hile the embryo-sac contains a relatively large female pro- 

 thallus, and as the pollen-grains of Angiosperms contain at 

 least one prothallus-cell, it is evident that the macrospore 

 [z.e., the enil)ry()-sac] of Angiosperms should contain not fewer, 

 and pr()lxil)ly more, prothallus-cells than the pullen-grain. 



As another objection against the acceptance of the spore- 

 nature of the nuclei, the following is given : " If we regard 

 them (the nuclei) as together representing a prothallial 

 structure, we jnay look upon the egg-cell as the etpiivalent 

 of the oosphere of Vascular Cryptogams ; but if not, we must 

 imagine a process of reduction carried past the point where 

 one might suppose everything had l)een removed but the 

 essentials — riot only the jjrothallus reduced to an oosphere, 

 but even beyond. Tiiis appeal's l)y no means easy to conceive, 

 and taken into consideraticjn along with what has been said 

 above, carries some weiglit." 



I shall take up these objections for discussion in the order 

 in which they have just been stated. Why should we expect 



