11. The male will then grow skin over the eggs to form a brood pouch . 12. The eggs are incubated inside the brood pouch for 30 to 40 days before hatching. 13. The females of " Tylomelania mahalonensis " usually have 1-11 embryos in their brood pouch . 14. The females of " Tylomelania towutica " usually have 1-7 embryos in their brood pouch . 15. The females of " Tylomelania masapensis " usually have 1-5 embryos in their brood pouch . 16. The females of " Tylomelania sarasinorum " usually have 1-14 embryos in their brood pouch . 17. The females of " Tylomelania abendanoni " usually have 1-4 embryos in their brood pouch . 18. Many species osmoregulate the brood pouch fluid to maintain proper pH for the developing embryos. 19. Males possessing brood pouches release their sperm directly into them; the pouches are then vigorously shaken. 20. After implantation in or on the brood pouch or brood patch, the male incubates the eggs.
