In the _Turdidæ_ the basal joint of the outer lateral toe is united to the middle toe, sometimes only a part of it; and the inner toe is cleft almost to its very base, so as to be opposable to the hind toe, separate from the others. In the _Troglodytidæ_, on the contrary, the inner toe is united by half its basal joint to the middle toe, sometimes by the whole of this joint; and the second joint of the outer toe enters wholly or partially into this union, instead of the basal joint only. In addition to this character, the open, exposed nostrils, the usually lengthened bill, the generally equal lateral toes, the short rounded wings, the graduated tail, etc., furnish points of distinction. Genera. A. Lateral toes very unequal. _a._ Culmen depressed basally, the interval between the nostrils wider than the much compressed anterior half of the bill. Plate on the posterior half of the tarsus continuous. Catherpes. _b._ Culmen compressed basally, the interval between the nostrils narrower than the rather depressed anterior half of the bill. Plate on the posterior half of the tarsus broken into smaller scales. Salpinctes. B. Lateral toes equal. _c._ Length about 8 inches. Campylorhynchus. _d._ Length less than 6 inches. Bill abruptly decurved or hooked at the tip. Outstretched feet not reaching near to end of tail. Thryothorus. Tail longer than the wing, the feathers black, variegated terminally with whitish … Subgenus _Thryomanes_. Tail shorter than the wing, the feathers rusty, not variegated with whitish … Subgenus _Thryothorus_. Bill only gently curved at the tip. Outstretched feet reaching nearly to or beyond the end of the tail. Back without streaks. No distinct superciliary stripe. Troglodytes. Bill curved, sub-conical. Tail as long as wing.… Subgenus _Troglodytes_. Bill straight, subulate. Tail much shorter than wing.… Subgenus _Anorthura_. Back streaked with black and white. Cistothorus. Bill short, stout; its depth equal to one half its length from the nostril; gonys straight or even convex, ascending. Crown streaked; no distinct superciliary stripe.… Subgenus _Cistothorus_. Bill elongated, slender; its depth less than one third its length from the nostril; gonys slightly concave, declining. Crown not streaked; a conspicuous superciliary stripe.… Subgenus _Telmatodytes_. GENUS CAMPYLORHYNCHUS, SPIX. _Campylorhynchus_, SPIX, Av. Bras. I, 1824, 77. (Type, _C. scolopaceus_, SPIX = _Turdus variegatus_, GMEL.) [Line drawing: _Campylorhynchus brunneicapillus._ 7149]