310 BIOLOGY. [BOOK iv. 



It is by bipartition that the polypiers are produced and the 

 humblest seaweeds and mushrooms -multiply. 



FIG. 43. 



Reproduction by segmentation of an elementary organism, amoneron: A, entire moneron. 

 (protamoeba) ; B, the same moneron divided into two halves by a median fissure ; C, the 

 two halves have separated, and constitute now independent individuals. 



At a higher degree of organisation it is no longer the 

 whole organism which is divided. The function is localised. 

 There is formed, often by genesis, a special cell, the ovulum, 

 charged to reproduce a new organic individual. This cell 

 always commences its labour of organic construction with a 

 series of bipartitions, with a segmentation ; whence result 

 numbers of new cells, of bricks, which are the first materials 

 of the future edifice. But usually to be fit to traverse its whole 

 evolutive cycle, the ovular cell needs a special impulsion. It has 

 to blend with another anatomical element, likewise special. The 

 element which segmentises and multiplies itself is called female. 

 That which impresses on it the evolutive impulsion is called 

 male element, and the process of union is one of the simplest : 

 it is the process of conjugation of which we have previously 

 given an example. The two cells come into contact : the female 

 element absorbs the male element, impregnates itself therewith, 

 and from that moment it is fecundated, and pursues the course of 

 its formative labour. In the two kingdoms everywhere there 

 are sexuality and fecundation ; whatever may be the complica- 

 tion o accessory organic apparatus, the fundamental fact 



