J. Chavadej et al., ROLES OF NEUROSECRETORY-CELLS ON GROWTH AND REPRODUCTION AND THEIR SEASONAL-VARIATION IN ACHATITA-FULICA (GASTROPODA, ACHATINIDAE), Journal of the Science Society of Thailand, 20(4), 1994, pp. 157-170
The injections of Achatina fulica with cerebral ganglion homogenate an
d with optic tentacle homogenate revealed that both substances had No
effect on body growth of A. fulica. However, the cerebral ganglion hom
ogenate appeared to increase the oocyte production in the ovotestis of
snails. Seasonal variation in number and size of neurosecretory cells
in the cerebral ganglia of A. fulica was observed The number of neuro
secretory cells in the cerebral ganglia was high during the rainy seas
on (May-October, 1993) and low during the dry season (November-April,
1993). The highest number of neurosecretory cells and the largest cell
size were observed in May. The number and size of collar cells in the
optic tentacles were similar throughout the year.