THE BIOLOGY OF FERTILIZATION AND BROOD PROTECTION IN SPIRORBIS (LAEOSPIRA) MORCHI

Abstract

1. Data obtained from Spirorbis morchi larvae reared from settlement to maturity in isolation, together with observations on isolated adults, provide evidence that Sp. morchi is capable of self-fertilization. Self-fertilization in Spirorbis is believed to be facultative and not obligatory. 2. The histology of the opercular brood pouch in Sp. morchi is described, and it is concluded that the only opening into the brood pouch is by means of an opercular pore. 3. Observations on the brooding behavior of Sp. morchi have led to the conclusion that spawning takes place when the animal is completely withdrawn into its tube. 4. An explanation as to how oocytes are deposited into the opercular brood pouch is advanced.