9. Acrocéphalus (Reed, Marsh, Sedge, and Aquatic Warblers). Bill nearly straight, with culmen elevated, wide at base, compressed towards tip, and slightly emarginate; edges of lower mandible inflected; nostrils basal, oblique, oval, and exposed; moderately developed bristles at gape. Forehead narrow, depressed. Wings rather short, first quill minute, third usually longest. Tail rounded, rather long. Legs long; feet large and stout, hind toe strong; claws long and moderately curved.
10. Locustella (Grasshopper Warbler). Differs from other Sylviinæ chiefly in its more rounded tail and longer under tail-coverts. The late Professor Newton found the tendons of the tibial muscles strongly ossified in this genus.
11. Phyllóscopus (Chiff-chaff, Willow and Wood-warblers). Bill slender, rather short; upper mandible decurved from middle and compressed towards tip, which is very slightly notched; nostrils basal, lateral, oblong, partly operculate, membrane clothed with small bristle-tipped feathers, internasal ridge very thin; gape beset with hairs. Wings rather long, first quill comparatively large, third or fourth longest. Tail slightly forked, twelve feathers. Tarsus scaled in front, rather long. Toes long, claws curved.
SUB-FAMILY REGULINÆ
Arboreal. Each nostril covered by a single stiff feather.
12. Régulus (Gold and Fire-crested Wrens). Bill very slender, awl-shaped, straight, compressed; cutting edges bent inwards about the middle; nostrils partly concealed by small bristly feathers, directed forwards; first primary very short, second much shorter than the third, fourth and fifth longest; tail moderate; tarsus slender, rather long.