Ferussaciids

Ferussaciids are a family of small, terrestrial gastropod molluscs commonly known as the "thin-shelled snails". They belong to the order Heterurethra, characterized by their unique reproductive anatomy. These snails are found in temperate regions worldwide, favoring moist habitats such as leaf litter, under logs, and in damp soil.

The shells of ferussaciids are typically thin, translucent, and ovate, often with a glossy surface. They are generally small, with adult sizes ranging from a few millimeters to about two centimeters in length. The aperture, or opening of the shell, is usually elongated.

Ferussaciids are detritivores, feeding on decaying organic matter, fungi, and algae. Their reproductive biology is a notable feature, with some species exhibiting simultaneous hermaphroditism, possessing both male and female reproductive organs at the same time. Reproduction typically involves internal fertilization.

Several genera are recognized within the family Ferussaciidae, including Ferussacia, Cecilioides, and Pseudamnicola, though classification can vary between sources. They are generally considered harmless to humans and play a role in decomposition within their ecosystems.