REPRODUCTION. 23 



possess t"he power of reproducing a lost limb, by means of a 

 bad which is gradual!}' developed, till it assumes the form and 

 takes the place of the missing- member. In these cases, how- 

 ever, the process is not in any way generative, and the pro- 

 duct of gemination can in no sense be spoken of as a distinct 

 being (or zooid). 



Another form of gemmation may be exemplified by what 

 takes place in the Foraininifera, one of the classes of the Pro- 

 tozoa. The primitive form of a Foraminifer is simply a little 

 sphere of sarcode, which has the power of secreting from its 

 outer surface a calcareous envelope ; and this condition may be 

 permanently retained (as in Lagena). In other cases a process 

 of budding or gemmation takes place, and the primitive mass 

 of sarcode produces from itself, on one side, a second mass 

 exactly similar to the first, which does not detach itself from its 

 parent, but remains permanently connected with it. This se- 

 cond mass repeats the process of gemmation as before, and this 

 goes on all the segments remaining attached to one another 

 until a body is produced, which consists of a number of little 

 spheres of sarcode, in organic connection with one another, 

 and surrounded by a shell, often of the most complicated de- 

 scription. In this case, however, the buds produced by the 

 primitive spherule are not only not detached, but they can only 

 remotely be regarded as independent beings. They are, in all 

 respects, identical with the primordial segment, and it is rather 

 a case of 'vegetative' repetition of similar parts. 



Another form of gemmation is exhibited in such an organism 

 as the common sea-mat (Flustra), Avhich is a composite 

 organism composed of a multitude of similar beings, each of 

 which inhabits a little chamber, or cell ; the whole forming a 

 structure not unlike a sea- weed in appearance. This colony is 

 produced by gemmation from a single primitive being (' poly- 

 pi de '), which throws out buds, each of which repeats the pro- 

 cess, apparently almost indefinitely. All the buds remain in 

 contact and connected with one another, but each is, neverthe- 

 less, a distinct and independent being, capable of performing 

 all the functions of life. In this case, therefore, each one of 

 the innumerable buds becomes an independent being similar 

 to, though not detached from, tho organism which gave it 

 birth. This is an instance of what is called ' continuous gem- 

 mation.' 



In other cases as in the common fresh-water polype or 

 Hydra the buds which are thrown out by the primitive or- 

 ganism become developed into creatures exactly resembling 

 the parent, but, instead of remaining permanently attached, 

 and thus giving rise to .a compound organism, they are de- 



