218 SUMMARY OF CONCLUSIOKS. 



which, in impregnation, a basis is formed for a 

 new cycle of changes of the same kind. 



§ 4. On the other hand, a ffarther expansion must be 

 given to the formula, to adapt it to cases of repeated 

 puUulation. For this purpose a middle term must be in- 

 serted under each head ; for, as has been showTi, a process 

 of puUulation m.ay be interpolated in any of its three stages. 

 Thus modified, the formula will stand as follows : — 



I. PROTOMORPHIC STAGE. 



Detelopment of the fecundated germ into a rudimen- 

 tar}^ form. 



PuUulation^ or production of a continued series of 

 gemm93, which are either detached, or remain in 

 connection with the stock as a compound organ- 

 ism — (Protonema.) 



Gemmation, or formation, in the concluding links of 

 the series, of new points of growth. 



. II. — ORTHOMORPHIC STAGE. 



Development of such gemmae into organisms of the 



typical form of the species. 

 PuUulation to a variable extent in this form — (a Poly- 



pidom or Vegetation.) 

 Gemmation, in the concluding pullulations, of fresh 



points of growth, for the evolution of sexual 



org^ans. 



III. — GAMOMORPHIC STAGE. 



Development of the latter gTowths into sexual structures 

 of greater or less complexity. 



