REPRODUCTION. 583 



and animal world, Nature has shown the utmost 

 solicitude to secure not only the mutiplication 

 of the species, but also the dissemination of their 

 numbers over every habitable and accessible 

 region of the globe; and has pursued various 

 plans for the accomplishment of these important 

 objects. 



The simplest of all the modes of multiplica- 

 tion consists in the spontaneous division of the 

 body of the parent into two or more parts ; each 

 part, when separated, becoming a distinct indi- 

 vidual, and soon acquiring the size and shape of 

 the parent. We meet with frequent examples of 

 this process of Jissiparous generation, as it is 

 termed, among the infusory animalcules. Many 

 species of Monads, for instance, which are natu- 

 rally of a globular shape, exhibit at a certain 

 period of their developement a slight circular 

 groove round the middle of their bodies, which 

 by degrees becoming deeper, changes their form 

 to that of an hour-glass ; and the middle part 

 becoming still more contracted, they present the 

 appearance of two balls, united by a mere point. 

 The monads in this state are seen swimming 

 irregularly in the fluid, as if animated by two 

 different volitions ; and, apparently for the pur- 

 pose of tearing asunder the last connecting 

 fibres, darting through the thickest of the crowd 

 of surrounding animalcules ; and the moment 

 this slender ligament is broken, each is seen 



