entom6straca and phyll6poda. 273 



The young pass through several stages before 

 they begin to .resemble the parent. It has been said 

 that the eggs are carried in the external ovaries only 

 until they are ready to hatch, when they are deposited 

 before the young make their escape. This is a mis- 

 take, as the student will probably soon observe. The 

 young leave the egg while they are still attached to 

 the parent, breaking the fegg membrane suddenly and 

 unexpectedly, although the observer may have been 

 for some time watching the little creatures restlessly 

 moving about inside. At their sudden escape they 

 often dart half-way across the field of a low-power ob- 

 jective. 



Fig. 186.— Cyclops wirh a young form. Fig. 187.— Limnitis. 



If Cyclops had no enemies the waters would soon be- 

 come filled with them in numbers almost beyond im- 

 'agining. One female. Cyclops has been seen to lay ten 

 times in succession; but, to be within bounds, the ob- 

 server who made the calculation supposes a single one 

 to lay eight times only, and forty eggs at each time. 

 "At the end of one year this female would have been 

 the progenitor of 4,442,189,120 young— that is, near 

 four and a half thousands of millions." 



19 



