What is "scaevatula"

Scaevatula is a genus of small predatory sea snails, marine gastropod mollusks in the family Clavatulidae.

Most gastropod species, and especially the marine species, have a dextral shell. The genus Scaevatula represents an exception to this rule, as the species are sinister. Within the family Clavatulidae, the extinct species Clavatula aralica (Luković, 1924) is the only other exception.