SUMMARY OF CONCLUSIONS. 213 



III. — Eeproduction, by fecundated germs, appears to be 

 of a higher kind than that by gemmse, and has been regard- 

 ed as the special agency for the propagation of the 

 species, the other serving rather for the extension of the 

 individual.* 



IV. — There may be reason to believe that the recurrence 

 of sexual generation, at least occasionally, is necessary for 

 the long-continued propagation of every species ; but, in 

 many of the lower forms of life, it occurs but rarely, and at 

 distant intervals. In the higher, again, it is the prevailing 

 mode, and the counter process of gemmation is minimized, 

 and its manifestations often very obscure. 



V. In those in the lower species, in which both modes of 

 propagation are well marked features, we find that they 

 have a tendency to succeed each other in a regular order, 

 to which the term of " alternation of generation" (meta- 

 genesis) has been applied. 



VI. — The phenomena of alternation of generations pre- 

 sent certain remarkable diversities, dependent in great 

 measure on the period of the life-history of the species at 

 which a distinct process of gemmation is interpolated. 



VII. — In some cases the interpolation takes place in 

 what has been termed here the protomorphic stage — that 

 is, in the course of development prior to the appearance of 

 the typical character of the species (as in Trematoda and 

 Mosses.) 



VIII. — More frequently, perhaps, a process of gemmation 

 is interpolated in the later or gamomorphic stage — that is, 

 in connection with the development of the reproductive 



* This idea, based partly on the greater resemblance to the parent, in 

 most cases, of the progeny developed by the budding process, has the 

 support of many great authorities. " Gemmce individium continuant, 

 cum semina speciem propagent,* is an aphorism of Link (Elem. Philos. 

 Bot., p. 208) ; that of Linnaeus is different — " Gemmcn totidem herbce." 

 Braun's Rejuvenescence, pp. 19, 24. 



