Heredity in Finidulus Hybrids i6l 



acteristics of the orgaii/sin, at least as late as the gastrida stage, are 

 derived entirely from the egg cytoplasrn"? 



The above statement is based largely upon certain experiments 

 of Godlewski, in which enucleated sea-urchin eggs fertilized with 

 crinoid sperm produced gastrulae of purely urchin type. Exam- 

 ination of Godlewski's records shows that in all these experi- 

 ments only four eggs developed at all and these did not produce 

 typical larvae. That this very meager piece of evidence is inade- 

 quate and unsatisfactory seems to be the opinion of subsequent 

 workers on echinoderm hybrids. It is certainly not sufficiently 

 well established to form the basis for any important conclusion. 



There is undoubtedly a close correlation between the degree 

 of normal functionality of the male nucleus in early development 

 and the degree of hereditary influence exerted by the latter. This 

 was shown in clear fashion by Baltzer/ who crossed four species 

 of sea-urchins in all possible ways and noted thatwhen there was 

 a complete elimination of paternal chromatin a pure maternal 

 type of larva resulted, and when the male chromosomes continue 

 to function more or less normally the larvae showed an admixture 

 of maternal and paternal characters. 



The results here discussed seem to point to the conclusion that 

 the nuclear material is the chief factor in determining the char- 

 acter of early development. As Fischel has ably pointed out, 

 the role of the spermatozoon is from the beginning formative in char- 

 acter in that it IS able to place the stamp of its own speotfic char- 

 acters upon the early dexwlopmental stages of the organism, tvhile 

 the egg cytoplasm furnishes only the material for the formative 

 operation of the combined nuclear material of the two parents. 



8Z00I. Anz. Bd. 35. 



