372 
developed further since my notes, at this stage, show them to be in a good 
condition. , 
Gasterostcus bispinosus, female, 
x 
Menidia gracilis, male. 
In two of the three experiments made with this cross, practically 100. 
per cent. of the eggs were normally impregnated. The eggs develop at the 
sume rate as the normals until the latter half of gastrulation, when the 
hybrids fall behind. Most of the eggs form embryos. These are short, with 
heavy anterior portion. The posterior one-half or one-third of embryo 
remains quite rudimentary. The anterior enlarged end develops eyes that in 
the earlier stages are apparently normal. The heart is formed and pul- 
sates. I have kept these embryos alive for five days. 
Gasterosteus bispinosus, female, 
x 
Tautoga onitis, male. 
Practically 100 per cent. of the eggs were normally fertilized in the 
single cross made. The eggs show the usual slowing in development at the 
close of segmentation. About 50 per cent. of the embryos died at a stage 
when gastrulation was from one-third to one-half completed. The remainder 
more or less completely closed the blastopore. The anterior portion of 
embryo is heavy. No eyes and heart were observed. The embryos died 
three days after closure of the blastopore. 
Gasterosteus bispinosus, female, 
* 
Tautoglabrus adspersus, male. 
Seventy-four per cent. in one experiment and practically 100 per cent. 
in the other were normally impregnated. The embryes developed more suc- 
cessfully than when Tautoga was used as the male. <A large per cent. of 
the eggs attempted to close the blastopore. The anterior end of embryo was 
large, eyes and heart were developed but not normally. The embryos lived’ 
for five days in this condition. 
Menidia notata, female, 
x 
Tautoga onitis, male. 
Eighty per cent. of all the eggs were normally fertilized. The embryos 
