I. Cycloid scales embedded in the skin. _A_. Eyes distinct, or concealed under the skin. _a_. Two series of teeth in the lower jaw. α. Quadrato-jugal (squamosal) and parietal bones in contact. Tentacle between eye and nostril. _Ichthyophis_, 2 species, India and Malay islands, p. 90. " below and behind nostril. _Hypogeophis_, 3 species, East Africa and Seychelles, p. 92. " below and in front of eye. _Dermophis_, 5 species, America and Africa, p. 93. " below the nostril. _Coecilia_, 6 species, America. β. Quadrato-jugal separated from parietal. Tentacle close to the eye. _Rhinatrema_, 2 species, America. " below and behind nostril. _Geotrypetes_, 1 species, West Africa. " below nostril. _Uraeotyphlus_, 3 species, West Africa and India. _b_. One series of teeth in the lower jaw. Tentacle in front of the eye. _Cryptopsophis_, 1 species, Seychelles. _B_. Eyes below the cranial bones. Quadrato-jugal in contact with{90} parietal. Tentacle near the nostril. _Gymnophis_, 4 species, South America. _Herpele_, 2 species, Panama and Gaboon. II. Without scales. _A_. Eyes distinct, or concealed under the skin. _a_. Two series of teeth in the lower jaw. α. Quadrato-jugal in contact with parietal. Tentacle behind nostril; end of body laterally compressed. _Typhlonectes_, 3 species, America, p. 93. β. Quadrato-jugal separated from parietal. Tentacle between eye and nostril. _Chthonerpeton_, 2 species, America. _b_. One series of teeth. α. Quadrato-jugal and parietal in contact; tentacle in front of the eye. _Siphonops_, 4 species, America. β. Quadrato-jugal separated from parietal. _Bdellophis_, 1 species, East Africa. _B_. Eyes below the cranial bones. _a_. Two series of teeth. Quadrato-jugal and parietal in contact; tentacle behind and below nostril. _Gegenophis_, 1 species, India. _b_. One series of teeth. Quadrato-jugal separated from parietal. _Scolecomorphus_, 1 species, East Africa. _Boulengerula_, 1 species, East Africa.