148 Society for Experimental Biology and Medicine. 



crested. Second hybrid generation includes both crested and 

 crestless birds. 



Series II. Inheritance of plumage color : Green canaries 

 crossed with yellow canaries give mottled offspring. Descendants 

 of these mottled offspring include some yellow and also some 

 green birds. 



Demonstration of Oenothera (evening primrose) and its mutants. 



Demonstration of brandling and branchless sunflowers. 



Demonstration by Miss Lutz of variability of chromosomes in 

 Oenothera and its mutants. 



Demonstration by Mr. F. E. Lutz of inheritance of abnormal 

 wing venation in the vinegar fly, Drosophila. 



102 (245) 



Further studies of the effects of the exposure of sperm to X rays. 

 By CHARLES R. BARDEEN. 



[From the Anatomical Laboratory, Uiiiversity of Wisconsin^ 



Eggs of Rana pipiens fertilized by sperm exposed to Roentgen 

 rays for one hour all develop abnormally. The abnormalities 

 begin to appear during the gastrulation period. Cases of spina 

 bifida are not uncommon. Out of a lot of several hundred eggs, 

 nearly all of which were fertilized, only one specimen survived two 

 weeks. This was much stunted in growth and very abnormal in 

 shape. Out of 80 eggs of the common toad exposed only 1 5 

 minutes to the Roentgen rays but 4 larvae have survived one 

 month. Most of the larvae were markedly abnormal in shape. 

 Of the survivors, two are large and apparently normal and two are 

 undersized. Only one individual out of 1 50 eggs fertilized by 

 sperm exposed 37 minutes to the rays has survived one month and 

 this individual is but half the normal length and breadth. Out of 

 250 eggs fertilized by sperm exposed to the Roentgen rays for an 

 hour and ten minutes, all exhibited marked abnormalities of 

 development and the least abnormal larva and longest survivor 

 died a week after the eggs were fertilized. 



The susceptibility of sperm of anura to the X rays is in marked 

 contrast to that of paramecia. Exposure of paramecia for 1 2 



