COMPENDIUM. 293 



viduality for ever, or until becoming extinct by means preventing its con- 

 tinuance, assuredly it is not througb the medium of metamorphosis that 

 new generations, — those different from the parent stock, can ensue. 



I apprehend that until final perfection, the living being, under what- 

 ever difference we behold it, is only in a state of transition, of longer or 

 shorter duration. 



If admitting, that, as is probable, all the organs subsequently dis- 

 played in maturity, exist in the germ or other elements of the animal 

 frame, metamorphosis seems to consist in what we deem the irregular 

 evolution of some parts, and the irregular contraction, decay, or disappear- 

 ance of others, while induration and other processes are advancing. 



Throughout the progress of metamorphosis, the animated being is 

 adapted by its form for the precise condition wherein it is placed. 



If the elements of the future product be a germ, this germ seems to 

 include the rudiments of the whole future specimen, not the elements of 

 the Hydra or Ascidia only, but of all their accessories. 



These are successively evolved, as more conspicuously seen in the pre- 

 ceding example of the compound Ascidia : also in the Fhtstra hispida, the 

 Alci/onium gelatinosum, and the Cristatella. 



The evolution of a single primitive animal is the foundation of all, 

 as in the Cristatella ; others are speedily generated, and the basis at length 

 serves as a common polyparium for the whole colony. 



The conversion of the active elements of the zoophytes, after discharge 

 from the matrix, to forms so different, succeeding their stationary state, 

 cannot fail to be compared to metamorphosis. This is not unexampled, 

 indeed, especially in the insect tribes, and in other animals. In the first 

 stage, however, the zoophyte is free : in the last it is fixed. Among other 

 creatures, some are free in the first stage, motionless in the second ; and 

 finally free again. Still a third race remains free, under great modifica- 

 tions, or a lower kind of transformation. 



The metamorphosis of most zoophytes ensues within a short time 

 after their production in the earliest stage, as planula, gemmule, or spi- 

 nula. All these soon appear under their ultimate aspect, in only a few 

 days. But a long time elapses in bringing the embryo of the lunate hydrse 



