Spawning and Hatching of a Clausiliid, Tyrannophaedusa mikado

Abstract

The present report deals with the result of observation on sexual behaviour, spawning and hatching of a Clausiliid, Tyrannophaedusa mikado, which was collected from Mt. Kinsho, Gifu Prefecture, and has been reared in petri dish for several years. 1. In copulation, the male inserts its penis into the genital opening of the mate. Mutual insertion of the penis, as is common in Bradybaena similaris, is not observed. 2. The longest record of copulation was for 7.5 hours. 3. The first spawning takes place within 38-60 days after the last copulation. Eggs were laid underneath wet cotton one per ovulation with interval of 2-17 days. 4. Egg is ellipsoid in shape and milky white in colour with the size of 4.37×2.12 mm. During the experiment, a single globular egg was found. Egg membrane is jelly-like, soft and innumerable crystals of CaCO_3 are embedded therein. 5. A single shell ovulates 4 to 19 times a year. 6. In hatching, young preys on the egg membrane from inside. It hatches out 13-15 days after spawning. The hatched young also preys on the empty egg.