EGG OF THE BRACHIONUS. 173 



Fortunately, the shell is so transparent that the interior of 

 the egg can be seen through it as if it were a mere film of glass. 

 The astonishing division and re-division of the yolk take place 

 before our eyes, being divided first into two, then into four, 

 then into eight, then into sixteen, then into thirty-two, and so 

 on, until the whole mass of the yolk is cloven into divisions too 

 numerous to count. 



By degrees, the form of the young Brachionus is developed 

 within the egg, even to the very teeth, which work away as 

 persistently as if large stores of food were being passed through 

 them. 



When the young is ready to take its place in the world, a 

 new development occurs, which has been well related by 

 Mr. Gosse: — 



" All these phenomena have appeared in the egg we are now 

 watching ; and at this moment you see the crystalline little 

 prisoner, writhing and turning impatiently within its prison, 

 striving to burst forth into liberty. 



" Now, a crack, like a line of light, shoots round one end of 

 the egg, and in an instant, the anterior third of the egg is 

 forced off, and the wheels of the infant Brachionus are seen 

 rotating as perfectly as if the little creature had had a year's 

 practice. 



" Away it glides, the very image of its mother, and swims to 

 some distance before it casts anchor, beginning an independent 

 life. At the moment of escape of the young, the pushed- off 

 lid of the egg resumes its place, and the egg appears nearly 

 whole again, but empty and perfectly hyaline (i.e. all but 

 transparent), with no evidence of its fracture, except a slight 

 interruption of its outline, and a very faint line running 

 across it." 



To pass from the egg to a more advanced stage in life. All 

 practical entomologists have been greatly annoyed, in their earlier 

 years of collecting, to lose larva after larva, from the attacks of 

 Ichneumon-flies. It is certainly rather beyond the limits of 

 ordinary patience to discover, watch over, and secure successfully 

 a rare caterpillar, and then to find that it has been " stung " by 

 an Ichneumon- fly. 



The veteran entomologist, however, troubles himself very 

 little about such minor misfortunes, and, as a rule, more than 



