1. Baxter, M. I., and R. H. Nisbet: Features of the nervous system and heart of Archachatina revealed by the electron microscope and by electrophysiological recording. Proc. Malac. Soc. Lond. 35, 167?177 (1963).
2. Böhmig, L.: Zur Kenntnis der sogenannten Dorsallappen des Gehirns von Limnaea stagnalis (L.) Lam. und Planorbis corneus (L.) Pfeiff. S.-B. Akad. Wiss. Wien, math.-nat. Kl., Abt. I 140, 319?335 (1931).
3. Boer, H. H.: A cytological and cytochemical study of neurosecretory cells in Basommatophora, with particular reference to Lymnaea stagnalis L. Arch. néerl. Zool. 16, 313?386 (1965).
4. ?, E. Douma, and J. M. A. Koksma: Electron microscope study of neurosecretory cells and neurohaemal organs in the pond snail Lymnaea stagnalis. Symp. zool. Soc. Lond. 22, 237?256 (1968).
5. Brink, M., and H. H. Boer: An electron microscopical investigation of the follicle gland (cerebral gland) and of some neurosecretory cells in the lateral lobe of the cerebral ganglion of the pulmonate gastropod Lymnaea stagnalis L. Z. Zellforsch. 79, 230?243 (1967).