TELEOST OVUM. 57 



elimination of both yolk-sac and germ substance as an effect of 

 the solvent action of the chemicals to which the eggs were ex- 

 posed. Whatever the mechanism involved in the production of 

 the recorded pathological ova may be, at the present time, it can 

 hardly be more than conjectured. It will be the object of future 

 investigations to find a satisfactory answer to this open question. 



There seems to be a close similarity between these cases where 

 parts of the germ-disc are apparently lost through elimination of 

 some kind and the production of hemiembryos by mechanically 

 injuring one of the blastomeres of the developing frog's egg, as 

 described by Roux, Morgan and other investigators. 



The writer intends to continue this work on the teleost eggs 

 as well as on the amphibian and hen's eggs. He also hopes that 

 he may in the near future secure adequate facilities for carrying 

 on experiments on the influence of the toxic substances of patho- 

 logical metabolism on the development of the mammalian em- 

 bryo. The plan of this work would be to mate animals in which 

 metabolic disturbances had been produced experimentally. 



A complete description and analysis of the results obtained in 

 the investigation reported here will be published at an early date. 



The writer takes pleasure in acknowledging his indebtedness to 



Professor C. R. Stockard of Cornell University Medical College 



with whom he on several occasions had discussed some phases of 



the work, and from whom he has received valuable suggestions 



regarding preservation of material. 



Marine Biological Laboratory, 

 Woods Hole, Mass., 

 September 3, I9i4' 



