Abstract
1. The spermatogenesis of the Indian apple-snail, Pila globosa Swainson has been described in this paper.
2. The spermatozoa are of two types, viz., the uniflagellate eupyrene and the multiflagellate oligopyrene. Only the eupyrene sperm has been described in detail.
3. Late spermatogonia and the spermatocytes reveal filamentous and granular mitochondria and a single duplex sphere.
4. The single duplex sphere divides into two by binary fission both during mitosis and meiosis.
5. In the spermatid the single duplex sphere secretes a small granular acrosome which later becomes conical. The duplex sphere is sloughed off.
6. The mitochondria of the spermatid fuse to form 6 to 8 balls. These later on elongate and form ribbon-like structures which give rise ultimately to the mitochondrial sheath of the middle-piece.
7. The head of the eupyrene sperm is also spirally twisted.
8. The oligopyrene sperm in this prosobranch is stumpy and short bearing 4 to 8 flagella. The cylindrical nucleus bears a small cap-like acrosome. The small middle-piece seems to be devoid of the mitochondria.
