PORIFERA, CCELENTERATA, VERTEBRATA 105 



structure concludes that it is not a special cell organ 

 but an artifact. Kulesch (1914), on the contrary, 

 finds it to be a constant organ in the eggs of the cat, 

 dog, and guinea-pig. 



The evidence of a continuous germ-cell cycle in 

 the vertebrates is more convincing than in the 

 sponges and coelenterates, and leads us to predict 

 that it will not be long before the gap still existing 

 during which germ cells cannot be recognized will 

 be filled in to the satisfaction of the majority of 

 investigators. 



