egg mass and growth rate of biomphalaria alexandrina under laboratory conditions

ABSTRACT

Egg masses of B. Alexandrina are always laid below the water surface in yellowish, rounded to oval, gelatinous masses. The egg mass ranges from 2.5 x 2 mm with 4 eggs to 8 x 5 mm with 39 eggs.The incubation period ranges between 11-15 day in February [15.1-20.3°C] and 6-9 days in August [26.l-31.1°C]. At hatching the shell diameter varies between 0.6-0.7 mm and attains maturity [6.8-7.2 mm] within 80-85 days