REPRODUCTION. 99 



Protozoa (fig. 26). 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, 

 fig. 26, A). In other cases a process of budding or gemma- 

 tion 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 second 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 



A B C 



Fig. 26. Diagram to illustrate the formation of the compound Foraminifera. A, 

 Simple form (Lagena), consisting of a sphere of sarcode, surrounded by a cal- 

 careous shell ; B, Compound form, produced by linear gemmation from a primi- 

 tive segment resembling A (Nodosaria) ; C, Compound form (Discorbina], in 

 which the buds are thrown out in a spiral, the coils of which lie in one plane. 



another, and surrounded by a shell, often of the most com- 

 plicated description. In this case, however, the buds pro- 

 duced 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 prim- 

 ordial segment, and it is rather a case of " vegetative " re- 

 petition of similar parts. 



Another form of gemmation is exhibited in such an 



