368 



Fundnlus Ueteroclitus, female. 



X 



Fun (lulu a cliaii.'.uiius, male. 



Fuudulus diaphanns was obtained from a fresh water lake, ami was 

 crossed many times in both directions with Fundnlus heteroclitus. In the 

 present cross I was never able to get a higher degree of impregnation than 

 80 per cent. Often I failed altogether and usually there was only an occa- 

 sional fertilized egg — less than 1 per cent. This may have been due partly 

 to the difficulty of getting enough good milt. In one instance I found about 

 one-half of the eggs polyspermia. The eggs develop along in a normal 

 fashion, going somewhat slower in the later stages, and hatch. I have 

 reared some of the embryos for two weeks and they seemed perfectly 

 active and otherwise normal. The eggs were reared in both fresh and sea 

 water. 



Fundulus diapJianus, female, 



X 



Funduhis hei( • ''ditus, male. 

 When Fundulus diaphanns is used as the female nearly all of the eggs 

 may be impregnated. Thus : 



Experiment 6b Nearly 100 per cent. 



13a " 62 " " 



18a " 91 " " 



The eggs are practically all normally fertilized and hatched. These I 

 have reared for twenty-two daj^s after hatching. 



Fundulus heteroclitus, female, 



X 

 Cynoscion regalis, male. 



The eggs of Fundulus are fertilized as perfectly with the sperm of the 

 Squetegue as with its own milt. Thus : 



Experiment 513 92 per cent. 



514 90 " '■ 



Only about 2 per cent, of the eggs are polysp^rmic. A tabulated outline 

 of the development compared with the normal is as follows : 



