210 RELATIONS OF OVA AND GEMMAE. 



of the nature of gemmation ; and the close affinity, if not 

 identity, which has now been shown to exist between the 

 processes of ovulation and gemmation is of especial interest 

 in this respect, that it indicates a parallelism between the 

 origination of the protomorphic stage, from the gamomorphic 

 structure of the preceding cycle, by the process of generation, 

 and the derivation of each of the other phases from that 

 which immediately precedes it in the same cycle. Just as 

 the typical form is budded off from the germinal, and as 

 the gamomorphic form itself is budded off from the or- 

 thomorphic, so is the germinal stage of the next generation 

 budded off in the form of an ovum from the female ovary. 

 That there should be certain specialities in this particular 

 gemmation is only what might be anticipated, when we 

 consider that the great function of this stage of existence is 

 the perpetuation of the race. Whenever the continuity of 

 the vital processes is broken in upon by a period of latency, 

 we find almost universally that this break follows close upon 

 ovulation, which is the characteristic gemmation of the 

 gamomorphic stage. Such a state of latent vitality is of 

 essential importance in the great majority both of animals 

 and vegetables, serving as it does to bridge over seasons 

 and circumstances which would otherwise prove fatal, and 

 affording, in the form assumed that of eggs or seeds 

 peculiar facilities for the dispersion of the species. An in- 

 termediate process of pullulation may occasionally occur in 

 the gamomorphic stage, but eventually eggs or seeds are 

 formed in almost every case.* An egg is itself essentially 

 a modified gemmae, derived from a gamomorphic structure ; 

 a seed is the persistent wall of such a gemma which has 

 already developed other structures in its interior; but both, 

 being destined for the continuation of the species, under 



* The Ferns and their allies constitute, perhaps, the only case in which 

 the reproductive organs remain permanently in adhesion to the typical 

 structures developed by their instrumentality. 



