Sinistrexcisa, a new genus of land snail from Central West Africa with four new species (Gastropoda : Pulmonata : Streptaxidae)

A new genus of Streptaxidae with four new species is described from Central West Africa, viz. Sinistrexcisa cameruniae (type species) from Southwest C ameroon, and S. iradieri, S. cogoensis and S. fang from Equatorial Guinea. In addition to the shells, the genital anatomy of three species and the rad ula of one species are described. The species of Sinistrexcisa resemble som e taxa of the heterogeneous genus Ptychotrema s.l. but differ conchological ly by, among others, the extremely long and displaced apertural sinus and t he sinistrally coiled last quarter whorl, and anatomically by the morpholog y of the penis, especially the inner spinulation. A spermatophore was obser ved in the lower (distal) portion of the penis of a specimen of S. fang. Th is is probably the first record of a spermatophore in the family Streptaxid ae.