_Osteocephalus taurinus_ Steindachner, 1862:77 [Holotype.--NHMW 16492 from Barra do Rio Negro, Manaus, Territorio do Amazonas, Brasil; Johann Natterer collector]. _Osteocephalus flavolineatus_ Steindachner, 1862:80 [Holotype.--NHMW 16495 from Cucui, Territorio do Amazonas, Brasil; Johann Natterer collector]. _Trachycephalus (Osteocephalus) taurinus_ Steindachner, 1867:64. _Osteocephalus planiceps_ Cope. 1874:122 [Holotype.--ANSP 11399 from Nauta, Departamento de Loreto, Peru; James Orton collector]. New synonymy. _Hyla taurina_--Boulenger, 1882:363 [synonymized _Osteocephalus flavolineatus_ Steindachner, 1862, with _O. taurinus_ Steindachner, 1862]. _Hyla planiceps_--Boulenger, 1882:364. _Hyla (Trachycephalus) vilarsi_ Melin, 1941:40 [Holotype.--NHMG 488 from Taracua, Rio Uaupes, Territorio do Amazonas, Brasil; Douglas Melin collector]. (_fide_ Bokermann, 1966:64.) _Hyla depressa_ Andersson, 1945:73 [Holotype.--NHRM 1966 from the Rio Pastaza watershed (? Provincia Pastaza), Ecuador; William Clarke-MacIntyre collector]. New synonymy. _Justification of Synonymy._--The holotype of _Osteocephalus taurinus_ is a female having a snout-vent length of 103.9 mm. The diameter of the tympanum is 6.8 mm, 77.3 percent of the diameter of the eye. The skull is strongly exostosed, and the lateral edges of the frontoparietals are elevated so as to form distinct ridges. The skin on the dorsum is smooth. When we examined the type on 5 August 1969, the specimen was soft and badly faded to a pale creamy tan with pale brown transverse bars on the hind limbs and spots on the flanks. Steindachner (1862:79) described the coloration of the type: "In the preserved specimen the dorsum of the entire body, including fore and hind limbs, is a light yellow-brown color, which becomes lighter towards the venter. The belly is whitish, as are the undersides of the arms and legs. The throat is indistinctly marbled with brown. Roundish dark brown flecks are randomly distributed in a considerable number along the side of the body up to the eye; the tympanum is more or less fully surrounded by brown. A few discrete spots, always more or less drawn out in length, on the sides of the body, are also found on the posterior part of the back. The dorsal surfaces of the fore and hind feet are marked with somewhat obliquely arranged brown transverse bands, which are more intensively colored near the margin than in the middle of the band." (free translation from German.)