. Annual report. 1st-12th, 1867-1878. Geology. 672 GEOLOGICAL SURVEY OF THE TERRITORIES. haemal spine, here fulfilling most important functions as the superior mandible, as it does throughout the class at large. In the Tetraonidw, as in the vast majority of birds, the intermaxillary or the "premaxillary" of some authors is of much stouter material than most other bones of the head, its use being a very obvious reason for this. (Plate V, Fig. 51, N. Pf. mx, i. mx.) From the moderately free fronto-maxillary and pseudo hinge-joint, between the out-turned frontals, the culmen of this bon
. Annual report. 1st-12th, 1867-1878. Geology. 672 GEOLOGICAL SURVEY OF THE TERRITORIES. haemal spine, here fulfilling most important functions as the superior mandible, as it does throughout the class at large. In the Tetraonidw, as in the vast majority of birds, the intermaxillary or the "premaxillary" of some authors is of much stouter material than most other bones of the head, its use being a very obvious reason for this. (Plate V, Fig. 51, N. Pf. mx, i. mx.) From the moderately free fronto-maxillary and pseudo hinge-joint, between the out-turned frontals, the culmen of this bone slopes by a gently increasing arc to the tip of the beak. This surface is rounded and split in two from the enlarged inner extremity to a point over the distal border of the nostril; this division lasts during life. The exter- nal nasal orifices are unusually large and sub-elliptical in outline. The head of the ethmoid shows in very young chicks, but is eventually cov- ered by this bone, which also fills in snugly the internasal space (Plate X, Fie1. 73).. Centrocercus tirophasianus. The osseous maxillary tomia are even sharper than when they were capped with the horny integumental sheath that the entire bill wears during life; they are produced backwards on a triangular process of the bone below the shaft of the maxillaries, touching them in the Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Geological and Geographical Survey of the Territories (U. S. ); United States. General Land Office; United States. Dept. of the Interior. Washington, Govt. Print. Off.
Size: 1487px × 1680px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1860, bookpublishe, booksubjectgeology
