Gonadal development and sex determination in pulmonate molluscs

Summary The development of the gonad, from hatching through sexual maturity and oviposition, has been studied in Arion ater rufus and Deroceras reticulatum. At hatching, the gonad is comprised of several acini. These acini are hollow structures, the walls of which are generally one or two cell layers thick. This cell layer consists of intermingled germinal and non-germinal cells. Eventually, each acinus is divided into two compartments (cortical and medullar) by a layer of auxiliary cells.The auxiliary cells appear to differentiate into Sertoli and follicle cells. These three non-germinal cell types appear to form an uninterrupted cell barrier that isolates the female germ cells in the cortex from the male germ cells in the medulla. Thus, although these animals are hermaphroditic, the male and female germinal lines differentiate in physiologically isolated compartments.Supported in part by NSF Traineeship Grant GZ-198.1 and NIH Developmental Biology Training Grant, No. 5-T01-HD00266-01.The author extends his thanks to Professors Alan J. Kohn, Edward C. Roosen-Runge, and W. Siang Hsu for their advice, suggestions, and encouragement.