314 THOMAS H. MONTGOMERY, JR. 



Fremiet, Retzius noted in mammals a "considerable reduction 

 in their substance as they enter into the formation of the spiral 

 thread." Jordan ('11) found that in spermatids of the opossum 

 a considerable number of mitochondria are cast off with the 

 cytoplasm; and while Duesberg ('10) maintains that in the 

 guinea pig all take part in forming the spiral thread of the sper- 

 matozoon, yet he figures granules with similar staining reactions 

 in the dehiscent cytoplasmic lobe. The parallel does not seem 

 yet to have been made, yet may not the "tingible corpuscles" 

 of mammalian spermatids be metamorphosed mitochondria, ones 

 that have nothing to do with the spiral threads? And now we 

 are able to adduce the positive case of Peripatits, in which all the 

 mitochondria become removed from the spermatozoon. 



In view of these facts it seems to me we should be very cautious 

 in attributing to the mitochondria a role in cellular activity at 

 all equal to that of the chromosomes. No spermatozoon ever 

 discards chromosomes, but that of Peripatns throws off all its 

 mitochondria. 



