369 
TABLE 8. 
LES PTS Ee PE 
TIME. FunpuLus X FUuNbDULUS. FunDULUS X SQUETE:UR. 
3.40 ep. M., July 17. Fertilization. | Fertilization. 
5.50 P. M., July 17. | 2 cells. 2 cells. 
6.35 Pp. M., July 17. | 4 cells. 4 cells. 
7.25 ep. M., July 17. | 8 cells. 8 cells. 
7.45 ep. M., July 17. | Begin. 16 cells. Begin. 16 cells. 
8.10 a. M., July 18. Late cleavage. Late cleavage. 
12.20 ep. m., July 18. Begin. germ ring. | Begin. germ ring. 
7.00 Pp. M., July 18. 3 over yolk. | Germ ring; } to $ over. 
8.15 a. M., July 19. Blast. closed; optic vesicles | Blast. closed; optic vesicles poorly 
plainly formed. formed notocord; scmites. Be- 
hind normals. 
2.15 Pp. M., July 19. Optic vesicles and lens; brown | Optic vesicles showing; behind 
parts showing. normals. 
Hatched. No further along. 
| 
The embryos mey continue their development to a stage where the eyes, 
heart, ear vesicles, tail, etc., are more or less well formed. At this stage 
they remain alive until about the time that the normals hatch. 
None of the embryos are formed even approximately normal. The indi- 
vidual differences are so great that a description of different forms would 
be of no avail. A brief description of one of the poorer embryos is as 
follows: The embryo may form a mere mass of cells so far as external 
appearances go. This embryo becomes pigmented with many pigment cells 
which are highly branched. It is bilaterally symmetrical in form, but the 
distribution of the pigment cells only slightly indicates this. In this em- 
bryo there was no definitely differentiated heart, but beneath and about one- 
third the distance back from the anterior end, a mass of cells could be seen 
regularly pulsating. Just above the heart-mass a vesicle occurred which 
I take to be the ear. There was no indication of a tail. I repeatedly ob- 
served the embryo bend itself from side to side so that there were prob- 
ably muscle tissues formed on both sides. This particular embryo died nine 
days after fertilization. 
One of the best formed embryos may now be described. Two eyes are 
tormed, although much too small, pocrly pigmented, without a lens and set 
into the anterior surface. Extending out on either side is a large vesicle 
which is probably an hypertrophied ear vesicle. A pretty well developed 
[24—26988] 
