THE BEGINNINGS OF LIFE. 549 



plex *^ sexual' method of reproduction. And, on the 

 other hand, amongst the more distinctly animalized 

 specimens of the Protista_, processes of fission and of 

 external gemmation gradually become mingled with 

 processes of internal gemmation or budding, as in the 

 Ciliated Infusoria. 



Whilst, outside the pale of the Protistic kingdom, we 

 find amongst Rotifers that fission and external gem- 

 mation for a time disappear, so as to give place to 

 a more frequent reproduction by internal buds or 

 ^ gemm«,' formed within a rudimentary ovarium. And, 

 similarly, amongst the Tardigrades, the mode of repro- 

 duction seems to be also for the most part of the 

 asexual variety — <^ gemmae' resembling ova being gene- 

 rally produced within an ovarium, a little more distinct 

 than that which is met with amongst Rotifers. But 

 the power of homogenetic reproduction in these re- 

 markable organisms is not limited to the rudimentary 

 generative organ. Dr. Gros tells us that the dead Tar- 

 digrade may ultimately be resolved into specimens of 

 Actinophrys, Peranemata, or Arcellinse by processes of 

 Pangenesis in every way similar to those occurring 

 amongst Rotifers ^ And whilst such heterogenetic pro- 

 ducts of the Tardigrade may, at different times, be 

 either all of one kind or variously intermixed, it occa- 

 sionally happens that two or three of the spherical 

 masses into which the body-substance becomes resolved 

 develop into young Tardigrades — even when the re- 

 ^ See pp. 483-486. 



