La familia Pyramidellidae Gray, 1840 (Mollusca, Gastropoda, Heterostropha) en África Occidental. 4. Los géneros Megastomia, Odostomia, Ondina, Noemiamea y Syrnola

The Atlantic species of the genus Odostomia (s. l.), nowadays divided in several genera, cited or found in the West coast of Africa (from Mediterranean to South Angola) are revised. For each species, the material studied and localities where they were found are indicated, as well as the geographic range of distribution, stablishing the names considered valid and their synonyms. In total, 95 species are studied: 22 of them are considered as belonging to the genus Megastomia, 58 to Odostomia, 6 to Ondina, 1 to Noemiamea and 8 to Syrnola. 31 species are described as new for science in the present work, but 3 of them without name due to its scarce material. A key to species on each genus is presented.