357 
TABLE 1. 
TIME OF OBSERVATION. Funp. X Funp. Founp. X Men. 
9.10 Pp. m.., June 26.! In 2 cells. | In 2 cells. 
9.40 Pp. m., June 26. Beginning 4 cells. | Beginning 4 cells. 
10.00 Pp. M., June 26. Completion 4 cells. Completion 4 cells. 
10.15 p. M., June 26. | Beginning § cells. | Beginning § cells. 
10.20 Pp. M., June 26. | Well begun on 8 cells. Well begun on 8 cells. 
10.30 p. m., June 26. | In8 cells. In 8 cells. 
11.00 p. M., June 26. Beginning 16 cells. | Beginning 16 cells. 
9.00 a. M., June 27. Well along in segmentation. | Well along in segmentation. 
9.00 Pp. m., June 27. Well begun on gastrulation. | First trace of gastrulation. 
9.00 a. M., June 28. 2+ over the yolk. | 3 or less over the yolk. 
3.00 Pp. M., June 28. Blastopore closed. 2 over the yolk. 
5.30 Pp. M., June 28. Blastopore closed, the embryo | Blastoporeclosing ornearly losed; 
long and narrow. | embryo much shorter than nor- 
mal. 
9.00 a. M., June 29. Embryo with optic vesicle. Blastopore closed, embryo short, 
no optic vesicle; apparently 
dead. 
"Pegs fertilized at 7 p. m., June 26. 
From this table it will be seen that the hybrids fall behind the nor- 
mals in their development. This becomes apparent only in the later stages. 
In the latter stages considerable irregularity in the rate of development 
obtains. Usuaily in a lot of eggs most of which have the blastopore just 
Closed, some eggs may be found that have just entered upon the gerim-ring 
stuge. Others may be variously further along. The number of such tardy 
eggs is usually small. These eggs may stop their development at various 
stages with consequent shortened embryos and incomplete blastopore closure. 
In this aberted condition they may live for days, forming pigment both in 
the embryo and in the yolk. This mass of cells may even develop a heart 
and ear vesicles. The heart beats for days without, however, handling any 
blood. From such condition to one where the embryo seems at first to be 
practically normal there are all stages. The great majority of the embryos 
die at a condition where the blastopore is closed, the embryo is laid down, 
though somewhat short, with pigment developed but no heart, eyes, ete. 
Some of the embryos, under favorable conditions, develop considerably 
further. In the more successful cf these the yolk becomes highly pigmented 
with both kinds of chromatophores. The same is true of the embryo. There 
is an attempt at pattern formation, showing bilateral symmetry but lacking 
