TWO PRINCIPAL MODES OF REPRODUCTION. 



553 



Mosses, and Hepaticae, as well also the " zoospores " of Algae, 

 belong to the same class of reproductive bodies. The gemmae 

 of Phanerogamia may be developed in connexion with the 

 parent .structure, and may continue to form a part of it ; or 

 they may be removed from it (as in the processes of budding, 

 grafting, &c.), and may be developed into new individuals. 

 On the other hand, the bodies of the second class are known 

 as seeds among Flowering Plants ; among the Cryptogamia 

 they present a variety of forms. From the very first, these 

 are destined to produce new individuals ; and although they 

 are often assisted in the early stage of their development by 

 the parent, they are its true offspring, rather than (like 

 gemmae) extensions of itself. Both these modes of Keproduc- 

 tion, namely, gemmation and sexual generation, exist in the 

 Animal Kingdom ; but the former is confined to its lower- 

 tribes, among which we often find it exercised in very remark- 

 able modes. 



Gemmiparous or Non-Sexual Reproduction. 



725. Among Infusoria ( 133) we find the process of gem- 

 mation, or of fission, which is a modification of it, to be almost 

 the only ostensible means of propagation which the beings 

 composing that wonderful group possess. The former may be 

 continually witnessed by the microscopic observer in the 

 common Vorticella, a bell-shaped animalcule attached by a stalk 



Fig. 295. VARIOUS FORMS OF ANIMALCULES, some of them undergoing spon- 

 taneous fission. 



(fig. 295, a, a), and abundant in almost every pool in which 

 aquatic vegetables grow, especially clustering around the stems 

 of Duckweed ; and its various stages closely resemble those 



