Note 13 — INTRODUCTION.

In the true conirostral or fringilliform genera the under mandible has high strong tomia, bent at an angle near the base; the corresponding portion of the upper mandible is deep, so that the nostrils are nearer the culmen than the tomia. The whole bill is more or less bent in its axis from the axis of the cranial base, so that the palate curves down, or is excavated or, as it were, is broken into two planes meeting at an angle,—one plane the anterior hard imperforate roof of the mouth, the other the back palate where the internal nares are situate (Sundevall). The single North American genus of Tanagridæ (Pyranga) is here conventionally ranged on account of its high nostrils and conic bill, although it does not show angulation of the tomia. The Icteridæ, with obviously angulated tomia, shade into the Fringillidæ in shortness and thickness of bill, and into other families in its length and slenderness.