373 
were followed to the closure of the blastopore. The embryos were shorter 
than normals. 
Tautoga onitis, female, 
x 
Menidia notata, male. 
In this cross 60 per cent. of the eggs were impregnated. Some dispermy 
and polyspermy occurred. There was a heavy mortality at the germ ring 
stage and subsequently. The ring spread about two-thirds over the yolk 
in some of them, when owing probably to bad conditions, all died. 
Fundulus diaphanus, female, 
x 
Eupomotis gibbosus, wale. 
The cross between the fresh water Fundulus and Eupomotis is from the 
standpoint of impregnation, much more successful than when the egg of 
Tundulus heteroclitus is used. The percentage of eggs fertilized may be 
as high as 70 per cent. 
Bixperimentsl24 cas cence eocenioce .56 per cent. 
rt Rarer rte evade oie, eat eRe © Kya 1) panied A 
fs Seats hs cy ee ke Reiner rie oles CORY AU ea be 
ae De Pree hd re ; avB hale u 
I have always found a considerable number of imperfect eggs which 
accounts in a measure for the usual low per cent. of eggs fertilized. A par- 
ticularly large number occurred in Example 17a. A few of the eggs are 
polyspermie in each experiment, probably, however, not many more than in 
the normals, where there may be as many as 5 per cent. polyspermic. The 
development stops when the protoplasm has spread about one-half over 
the yolk. Embryonic ring and shield are formed, but very little evidence of 
embryonic differentiation being shown in the shield. The protoplasm looks 
granular and opaque instead of clear, as in the normals. 
Opsanus tain, female, 
x 
Fundulus heteroclitus, male. 
In the one experiment made, twenty-one out of thirty-seven eggs were 
found in the 2 and 4-celled stage eight hours and twenty-five minutes after 
fertilization. A few of the eggs were polyspermic, They were followed to 
later cleavage. 
