All species, except _guttilatus_, have well-defined to poorly defined lateral fringes on the toes. All species have expanded toe pads. The fifth toe is usually shorter than the third, but the second is equal in length to the fifth in some specimens of _S. cystignathoides_ and _S. marnockii_. _Syrrhophus nivocolimae_ is the only species with tubercles along the outer edge of the tarsus; this is merely a reflection of the highly tuberculate nature of the skin in this species. _Skin texture._--The skin of the dorsum is smooth or very weakly pustular in all species of the genus except _nivocolimae_ and _verrucipes_. The dorsal surfaces of _nivocolimae_ are warty; in _verrucipes_ the skin is pustular. The skin of the venter is areolate in _cystignathoides cystignathoides_, _dennisi_ and _verrucipes_ but is smooth in all other species of the genus. [Illustration: FIG. 3: Plantar views of feet of four species of the eastern complex of _Syrrhophus_. (A) _guttilatus_ (UIMNH 55519, x6), (B) _leprus_ (UIMNH 42726, x6), (C) _verrucipes_ (UIMNH 15995, x6), and (D) _longipes_ (TCWC 12179, x4.6).] _Color pattern._--As is evident in the diagnoses, the color patterns of given populations have been regarded as useful in separating the species and subspecies. Duellman (1958) suggested that the coloration, with the exception of _modestus_, was a dark ground color with pale markings. It is a moot point whether the frogs have light spots on a dark background or have a light background with an extensive reticulate dark pattern. The venters are gray or white, and the vocal sac is nearly black in some species. Interorbital dark bars or triangles are absent in only two species of the eastern complex, _cystignathoides campi_ and _marnockii_; the latter lacks a supratympanic stripe, which is present in the other members of the eastern complex. _Syrrhophus interorbitalis_ and _nivocolimae_ have light interorbital bars; these bars occur in only one other population of the genus (_S. c. cystignathoides_). Bars on the thighs are ill defined or absent in the members of the _marnockii_ and part of the _modestus_ groups. The color in life is noted in the species accounts. _Voice._--The voices of all _Syrrhophus_ can be described as a single short chirp or peep; without audiospectrographic analyses the significance of the differences between a chirp, peep, or short whistle cannot be appreciated. Martin (1958) and Wright and Wright (1949) reported multi-noted calls, and one collector of _S. verrucipes_ noted the frog "trilled." Fouquette (1960) presented analyses of two species (_marnockii_ and _pipilans nebulosus_). The voices were very similar; both frogs were reported to "trill" and "chirp." SYSTEMATIC ACCOUNT