GERM CELLS OF GRYLLOTALPA 307 



chondria to be thrown to one pole. In some cases the first 

 cleavage plane cuts the egg so as to leave all the mitochondria 

 in one of the first two blastomeres and none in the other. She 

 found that each of these blastomeres, when separated, developed 

 into a normal larva. She concludes that the mitochondria are 

 not a vital part of the protoplasm, but only highly differentiated 

 products. 



Before discussing my own results I wish to describe briefly 

 two observations which have been made on Gryllotalpa vulgaris. 

 Buchner ('09) figures the mitochondria in the spermatogonial 

 cells as very similar to those in Gryllotalpa borealis (plate I, A) . 

 The only chromatin he finds in the nucleus at this time is in two 

 nucleoli, which are partly chromatic and partly achromatic. 

 The rest he believes to have passed through the nuclear wall 

 into the cytoplasm to form the mitochondria. According to 

 Buchner the mitochondria disappear before the next division. 

 Duesberg ('10), in the same form, finds the mitochondria very 

 much as Buchner figures them but finds no proof that they are 

 of nuclear origin. He also shows them to be present in mitosis. 

 Here is a case where two observers working on the same mate- 

 rial reach opposite conclusions. I can see how two observers 

 working on the same material might differ as to interpretation, 

 but I see no reason why they should differ so much in their 

 observations. In this case one or the other has certainly made 

 an error. 



From my own observations I cannot speak as to the origin of 

 mitochondria. They are present in large numbers in the sper- 

 matogonial cells. Judging from their mass here and in the 

 growth period, it would seem that they increase, but, again, I 

 have no direct information as to how this is accomplished. As 

 I find within the mitochondrial mass in the early growth period, 

 a spherical body which might be interpreted as a sphere, I wish 

 to mention Vedovsky's viewpoint as to the origin of mitochon- 

 dria. I have not seen his original paper, but Duesberg ('11) 

 quotes him as stating that the mitochondria are simple products 

 of the protoplasm, arising through the regressive transformation 

 of the centroplasm. Perhaps this central body in Gryllotalpa 



