364 
TABLE 4. 
TAUTOGLABRUS TAUTOGLABRUS 
TIME. 4 x 
| TAUTOGLABRUS. | FuNnpDULwts. 
9.30 ep. M., July 4. Fertilized. Fertilized. 
10.30 p. m., July 4. Two cells. | Two cells. 
10.45 p. M., July 4. Begin. 4 cells. | Close of 2 cells. 
10.50 p. M., July 4. | Well along in 4 cells. | Begin. 4 cells. 
11.00 vp. m., July 4. | Close of 4 cells. | Well along in 4 cells. 
11.10 Pp. M., July 4 | Well begun on 8 cells. Close of 4 cells. 
11.15 p. M., July 4. Well along in 8 cells. | Begin. 8 cells. 
11.30 p. M., July 4. Begin. 16 cells. | Close of 8 cells. 
11.55 p. M., July 4 | 16-+cells. 16+ cells. 
Fundulus heteroclitus, female, 
x 
Tautoga onitis, nrale. 
The percentage of eggs fertilized in the three experiments made was as 
follows: 
Experiment 104 ‘ .66 per cent. 
“ 108 40" 
e 506 ares ad ih 
It is not probable that with perfectly fresh milt the percentage would 
be higher. I have observed, the sex products of both sexes in this species 
materially deteriorate upon confinement of the fish, even for a short time. 
In experiment 506 good eggs were used and perfectly fresh milt in abun- 
dance was used. Practically all of the fertilized eggs are normally impreg- 
nated. In experiment 506 every impregnated egg was normal. 
The development proceeds in the same manner as in the cross between 
Fundulus and Tautoglabrus. Most of the eggs form a definite embryonic 
rim and an apparently normal embryonic shield, but even though they 
may go to the closure of the blastopore, the embryo is always much too 
short, never exceeding one-half the normal length. They are mostly shorter 
than this, a mere thickened mass of cells developed in the embryonic shield. 
In some cases the blastopore is practically closed, surrounded by a broad 
embryonic rim with the embryonic shield devoid of any embryo, 
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