The anatomy and taxonomy of two western African nassariids are explored, based on samples collected in Morocco. The species are Dorsanum miran, the type species of the genus, and Bullia granulosa, a characteristic member of Bullia. Both possess the typical morphological and anatomical features of the family, including a pair of metapodial tentacles, a well-developed proboscis, elongated odontophore with fusion of cartilages, and highly concentrated central nervous system. Both species have in common the socket-like heads, bifid columellar muscles, and reduction of the gland of Leiblein. D. miran has well-developed eyes, cement gland, and preputial protection at the penis tip. B. granulosa lacks eyes, has multiplicity of some buccal mass muscles (transverse muscles and main dorsal tensor muscles — m2), and a thick-walled and broad anterior oesophagus. The characters are discussed in the light of present knowledge concerning caenogastropod taxonomy.