6o 



CYTOLOGY 



CHAP. 



exact limits cannot be made out. Other species of Copepoda exhibit 

 intermediate conditions. 



Hacker (1893) made the interesting observation that the degree of 

 diffusion of the chromosomes during the germinal vesicle stage may vary 

 in a single species. Cyclops and the allied genera of Copepoda mostly 



FIG. 24. 



The chromosomes during the oogenesis of Heterocope saliens from the pachytene stage (A), through the 

 germinal vesicle stage (B, C) to the condensation of the definitive bivalents (D). (Matschek, A.Z., 1910.) 



lay their eggs in batches, of about ten to about a hundred at a time. The 

 eggs when laid do not leave the animal completely, but are cemented 

 together into masses, the so-called egg-sacs, which are carried about by 

 the animal until they hatch. A new batch of eggs is not laid till the 

 previous batch has hatched. 



In females of Cyclops strenuus which have not yet laid any eggs, no 



