Calcium phosphate granules in the reproductive system of Oxychilus atlanticus (Gastropoda : Pulmonata)

The presence of connective interstitial cells in the wall of several organs of the distal reproductive system in Oxychilus atlanticus is described by means of scanning electron microscopy (SEM). Connective interstitial cells extend from the distal part of the vas deferens to the penis, being the dom inant cell type of large portions of the epiphallus as well as in the whole penial caecum (=flagellum). These cells are highly mineralized and are cha racterized by the presence of large amounts of solid spherules (up to 4 mu m in diameter) in their cytoplasm. A semi-quantitative evaluation by X-ray microanalysis demonstrates that calcium and phosphorus are the main element s of the spherules. Their function is unknown, but they could aid in copula tion or they could assist the survival of the transferred spermatozoa.