EXPERIMENTS IN HEREDITY 175 



different order of echinoderms. The larvae of these two types 

 are easily distinguished even in early stages of development. The 

 larvae produced by fertilization of normal eggs of Echinus with 

 sperm of Antedon are said to be of the maternal type. This 

 result is in itself very remarkable, but Godlewski was also able to 

 fertilize enucleate egg fragments of the sea-urchin with sperm of 

 the feather star. Eight larvae produced in this way reached the 

 blastula stage, but only four developed as far as the gastrula. 

 These four, however, were again of the maternal type, and could 

 only be distinguished by their size from those of the pure Echinus 

 culture. From these experiments Godlewski concludes that 

 cytoplasm as well as chro matin must be concerned in the trans- 

 mission of hereditary characters, for no maternal chromatin was 

 present in the eggs from which the larvae developed. Whether 

 these results, which are in direct opposition to those of Boveri, 

 will be confirmed or refuted by further observations remains to 

 be seen. Walker, in his recent work on heredity, 1 has accepted 

 Godlewski's conclusions and made use of them in support of the 

 theory that the chromosomes are the bearers of individual 

 characters only, while racial characters may be transmitted by 

 " the whole protoplasm of the cell." 



1 " Hereditary Characters and their Modes of Transmission," by C. E. Walker 

 (London, Edward Arnold, 1910). 



