136 VIGNETTES FROM INVISIBLE LIFE. 



are extended and expanded in all their glory 

 the sovereign, yet social., crowned heads of the 

 Rotifers. 



In reference to the position which the Rotifera 

 occupy in the scale of animal life, it should be 

 noted as a fact of great significance that in 

 their history there is no intermediate or larval 

 condition after birth. All changes or metamor- 

 phoses take place in the egg, whence the embryo 

 emerges as near the exact counterpart of its 

 parents as generally obtains in the larger animals 

 with which we are familiar. There is an ap- 

 parent exception to this rule in the Floscularia, but 

 it is of a very slight and transient nature, and it 

 stands out as a remarkable fact, indicating or 

 calling attention to the general rule, and pointing 

 its importance and meaning, which may thus be 

 stated : Presuming, or taking for granted, that 

 the progress observed in organic forms of life, from 

 very simple to very complex conditions, is not achieved 

 or produced by leaps and bounds, but is rather 

 slowly and, it may be, even painfully reached in 

 a severe struggle for existence, it follows that when 

 a creature, however small, is found having a very 



