58 



The pollen-tube or filament (a, fig. 1) discharged from 

 the pollen-cell (a 1 ) in the plant represents the spermatozoon 

 (a, figs. 2 & 3) in the animal : its contents whether by 

 endosmose or perforation is immaterial are received by 

 the ovule (b, fig. 1), which is afterwards discharged and 

 becomes free. Under favourable circumstances the forma- 

 tion of the embryo takes place, with manifold modifications, 

 but essentially by the multiplication of cells, according to 

 a process which is as much entitled to be called continuous 

 growth as that process in the formation of the Conferva. 

 The embryo (c) proceeds to develope the radicle and the 

 plumula (d) by the metamorphosis and coalescence of certain 

 of the impregnated cells, retaining the major part, however, 

 as cells : and thus the first individual plant, or pair of in- 

 dividuals as in Dicotyledons, is established. 



The ovum (#, fig. 2) of the zoophyte proceeds to develope 

 its free locomotive embryo (c) by an analogous multipli- 

 cation of cells, certain of which are metamorphosed into 

 an external skin with vibratile cilia: the embryo settles, 

 subsides, shoots out rays, analogous to the radicle of the 

 plant, but for attachment only, and grows afterwards, as a 

 stem, from which a polype (d) is speedily developed an- 

 swering to the first cotyledon al leaf, or leaves, in the plant 

 (d, fig. 1). Both plant and zoophyte proceed to develope 

 by gemmation, the one a succession of leaves (ee), the 

 other of polypes (e e), associated by the continuous growth 

 of the connecting parts : and finally the plant by a meta- 

 morphosis of part of the stem and certain leaves produces 

 the flower or fructification (/*, g, h, i), and the zoophyte by 

 a modification also of its stem and certain polypes produces 

 an ( ovarian vesicle ' (f) or a modified polype (g) 9 or a me- 

 dusiform individual (/), which is set free : in both cases the 

 end to be attained is the diffusion of the species by means 

 of impregnated seeds or ova. 



Now, if we compare with the preceding the third figure 

 (fig. 3), in which I have represented the corresponding 



