Histological and Histochemical Observations On the Reproductive Tract of the Hermaphrodite Pond Snail Lymnaea Stagnalis (L.)

Abstract

The reproductive tract and the egg mass of Lymnaea stagnalis have been studied histologically and histochemically. The hermaphroditic duct is built up of neutral staining ciliated cells. In its distal portion the duct has large diverticula, the vesiculae seminales, which consist of large foamy cells. These cells ingest and destroy sperm. A groove with highly ciliated cuboidal or cylindrical cells is present along the length of the hermaphroditic duct. This groove is maintained throughout the greater part of the female tract, but in the male part was only observed in the prostate gland. The secretory cells of the albumen gland produce galactogen and proteins. In the rest of the female part 11 different secretory cell types could be distinguished. These cells produce different types of acid mucopolysaccharides or neutral polysaccharides. The histological findings account for 8 divisions of the female tract: 1. the albumen gland; 2. the posterior and anterior pars contorta; 3. the muciparous gland; 4. the pars recta; 5. the oothecal gland; 6. the uterus; 7. the vagina; 8. the bursa copulatrix. The histochemistry of the different parts of the egg mass is compared to that of the female tract and in this way an attempt is made to elucidate the function of the various parts of this tract. In the male part (sperm duct, prostate gland and penial complex) 13 secretory cell types were distinguished, viz., 3 in the sperm duct, 5 in the prostate gland and 5 in the praeputium. The sperm duct and the prostate gland produce mainly phospholipoproteins with some components consisting of polysaccharides and neutral fats. The function of these secretion products is assumed to be nutrition of the sperm. The secretory cells of the praeputium produce acid mucopolysaccharides, which probably play a role during copulation.