1 68 ROTIFER A. PART in. 



Some Kotifers are remarkably fertile. Professor 

 Ehrenberg estimated that, in the course of twenty-four 

 days, the offspring of a single individual of the genus 

 Hydatina might amount to seventeen millions. Female 

 eggs laid in autumn are collected in heaps and covered 

 with a gelatinous substance, which protects them from 

 the cold in winter, though the Eotifers themselves are 

 sufficiently protected by their great tenacity of life. 

 They revive after being frozen ; they may be dried for 

 an unlimited time, but, as soon as they meet with 

 warmth, moisture, and food, they resume their vitality. 



