_Turdus_, LINNÆUS, Syst. Nat., ed. 10, 1758, 168. (Type, _Turdus viscivorus_ of Europe.)—BAIRD, Rev. Am. Birds. GEN. CHAR. Bill conical, subulate, shorter than the head; the tip gently decurved and notched (except in _Hesperocichla_); the rictus with moderate bristles; the wings rather long and pointed, with small first primary (less than one fourth the second); wings considerably longer than the tail, which is firm, nearly even, with broad feathers. Tarsi variable, seldom as long as the skull, the scutellæ fused into a continuous plate, only in rare individual instances showing indications of the lines of separation. The genus _Turdus_ is very cosmopolitan, occurring nearly throughout the globe, excepting in _Australia_, and embraces species of highest perfection as singers. In the large number of species known there are many variations in external form, but the transition from one to the other is so gradual as to render it very difficult to separate them into different genera. The sections of the group we adopt are the following:— _Sexes similar._ Hylocichla. Smallest species. Bill short, broad at base; much depressed. Tarsi long and slender, longer than middle toe and claw, by the additional length of the claw; outstretched legs reaching nearly to tip of tail. Body slender. Color: above olivaceous or reddish, beneath whitish; breast spotted; throat without spots. Turdus. Bill stouter and higher. Tarsi stout and short, scarcely longer than middle toe and claw. Body stout, generally whitish beneath and spotted. (Second quill longer than fifth?) Planesticus. Similar to preceding. (Second quill shorter than fifth?) Beneath mostly uni-colored; unstreaked except the throat, which is whitish with dark streaks. _Sexes dissimilar._ Merula. Similar to _Turdus_. Male usually more or less black, especially on the head; females brownish, often with streaked throats. Bill distinctly notched. Hesperocichla. Similar to _Turdus_. Male reddish beneath, with a black collar. Bill without notch. SUBGENUS HYLOCICHLA, BAIRD. _Hylocichla_, BAIRD (s. g.), Rev. Am. Birds, 1864, 12. (Type, _Turdus mustelinus_.) [Line drawing: _Turdus mustelinus._ 1570] The essential characters of _Hylocichla_ have already been given. The subgenus includes the small North American species, with _Turdus mustelinus_, Gm., at the head as type, which are closely connected on the one side with _Catharus_, by their lengthened tarsi, and with _Turdus_ by the shape of the wing. The bills are shorter, more depressed, and broader at base than in typical _Turdus_, so much so that the species have frequently been described under _Muscicapa_. It is not at all improbable that naturalists may ultimately conclude to consider the group as of generic rank.