Ultrastructural analysis of the morphology and function of the spermatheca of the pulmonate snail, Sonorella santaritana

The ultrastructure of the spermatheca of the reproductive tract in the pulmonate snail, Sonorella santaritana, was investigated. This organ has a debris‐filled lumen and an outer wall which can be divided into three distinct layers. The cell layer adjacent to the lumen is comprised of two cell types, tall columnar epithelial cells with microvilli and cells lacking microvilli. The next layer also has two cell types, muscle cells and apparent pigment cells. The most distant layer is an adventitia of large glycogen‐containing cells. The lumen of the spermatheca contains a core of partially digested sperm and related materials. The luminal contents and the cellular morphology of this organ suggest that the spermathecal functions are both digestive and absorptive. It is proposed that excess sperm and related materials are transported to the spermatheca, digested, and the usable products are reabsorbed.