366 / J / / 
of the development rate, etc., in the normals and hybrids are included in 
Table 6. 
TABLE 6. 
TIME. | GASTEROSTEUS X GASTEROSTEUS. GASTEROSTEUS X FUNDULUsS. 
| 
——————_—_ + ——_——. — 
| 
1.05 p. M., June 4. | Fertilization. | Fertilization. 
4.00 p. M., June 4. | Two cells. _ Two cells. 
4.30 p. M., June 4. In 4 cells. | In 4 cells. 
4.45 p. M., June 4. Tn 4 cells. In 4 cells. 
4.55 Pp. M., June 4. | Begun on 8 cells. Begun on 8 cells. 
5.15 p. M., June 4. | Close of 8 cells. | Close of 8 cells. 
5.25 p. M., June 4. Begin. 16 cells. | Begin. 16 cells. 
6.05 p. M., June 4. In 32 cells. | In 32 cells. 
9.15 a. M., June 5. Late segmentation. Disk begin. | Late segmentation. Disk less 
to spread. . spread than in normals. 
11.40 a. m., June 5. Germ ring well formed. No indication of germ ring. 
2.00 p. m., June 5. Germ ring and embryonic shield. | No indication of germ ring. 
7.00 p. m., June 5. | 3 over yolk. | Germ ring and shield well de- 
| veloped. 
6.30 a. M., July 6. Blastopore closed. Embryo | 4 to 3 over yolk. 
formed. 
8.00 a. m., June 7. Embryo developed with eyes, | } overto closure of blast. Embryo 
brain, ete. | short and completely formed. 
! 
Fundulus heteroctitus, female, 
xX 
Stenostonmus chrysops, male. 
In this cross there is always a fairly large proportion of the eggs 
fertilized. The per cents in four experiments were as follows: 
Experiments 103b Soe spk Vesa ee UIDeR CON ts 
* LUG) eine vars toes 5 ice See ete vs 
NAS res ae sigh adn oe ee At. Pa 
+ GS iv adage ork Rees esrteta a ets air Che ee 
There is usually a considerable proportion di- and poly-spermic. This 
amounted to 18 per cent. and 20 per cent. in two experiments in which the 
count was made. The eggs would develop to the closure of the blastopore 
with the embryo teo short though considerably better formed than in the 
cross Fundulus heteroclitus and Tautogolabrus adspersus. The embryo in 
some cases may be two-thirds normal length, with the blastopore remaining 
a rather large oval or slit. Quite a variety of conditions in blastopore 
closure obtain here, but do not merit detailed description. The relative rate 
of development for the normals and hybrids is detailed in Table 7. 
