Introduction

Until recently, the New Zealand and Subantarctic Athoracophoridae have been a somewhat neglected group. Most workers on the Athoracophoridae have confined their attention to taxonomy and anatomy, and little has been paid to the finer details of their organisation, or to their ecology, development, feeding habits, breeding behaviour, and genetics. There are, of course exceptions, one of the more notable being a contribution by Plate (1898), who investigated the structure of the dorsal tracheate lung and of the renal system in some detail. However examination of reproductive systems has always been limited to dissection alone.

Reproductive systems of a number of species of New Zealand Athoracophoridae have been described by Hutton (1881), Plate (1898), Suter (1913), Burton (1962, 1977), and Climo (1973). The most obvious differences in anatomy between the various species lie in the relative arrangement of the prostate gland (referred to as the bulbose gland by Suter), the uterus, the spermatheca, and the oviducal gland. The naming of the oviducal gland has caused considerable confusion in the past; it has been variously referred to as the glomerate gland by Suter (1913) and Burton (1962, 1977), as the shell gland ("schalenblaschen"—literally shell bubble) by Plate (1898), and as the uterus by Climo (1973). Names put forward for a similar structure in other families of terrestrial slugs include "female gland" in Arion ater (Smith, 1966), "nidamental gland" in Philomycus carolinianus (Kugler, 1965) and "oviducal gland" in Agriolimax reticulatus (Boyne, 1966). Out of this nomenclatural plethora the term "oviducal gland" was finally selected for two reasons. First, the reproductive system of Athoracophorus bitentaculatus appears very similar in structure and function to that of Agriolimax reticulatus. Second, the lumen of the gland does form the oviduct; the uterus is a much more muscular structure, and quite different in function.

The present study describes the form of the reproductive system and some of its histological features, and the object of the paper is to provide a foundation on which to base further studies on the histochemistry and function of the reproductive systems of the Athoracophoridae, and on their breeding cycles.