Fifty-eight taxa of the genus Trachelomonas Ehrenberg 1833 sampled in Agneby river and in two little ponds at Adahou-village and Akressi (Ivory Coast) have been examined using scanning electron microscopy. The fine structure of the lorica surface was studied based on one hundred and sixty-four micrographs grouped in twenty-one plates giving general and detailed views of the cells. Among the fifty-eight taxa recorded, twenty-two are new for Africa, twenty-nine for West Africa and thirty-four for the Ivory Coast. Four species and seven varieties new to science are proposed, namely : Trachelomonas akressiensis, T. comperei, T. diploperforata, T. saccasii, and Trachelomonas armata var. assemienii, T. curta var. longicollis, T. hispida var. spinosa, T. lotharingiae var. adahouensis, T. saccasii var. paucigranulata, T. sculpta var. africana and T. sculpta var. dossahouae.