. A manual of zoology. Zoology. Fig. 597.—A, true; B, false nipple (after Gegenbaur). facial portions cannot be drawn. So it becomes necessary in describing the skull not to follow exactly the model adopted so far, but to take that of human anatomy. In the hinder region of the skull is a large occipital bone (figs. 517- 519), jointed to the atlas by double occipital condyles, and arising by the fusion of the four occipitalia, p. 458. Besides it includes usually a mem- brane bone, the interparietal, which occurs only in mammals. This is, strictly speaking, a paired bone, arising in the angle be
. A manual of zoology. Zoology. Fig. 597.—A, true; B, false nipple (after Gegenbaur). facial portions cannot be drawn. So it becomes necessary in describing the skull not to follow exactly the model adopted so far, but to take that of human anatomy. In the hinder region of the skull is a large occipital bone (figs. 517- 519), jointed to the atlas by double occipital condyles, and arising by the fusion of the four occipitalia, p. 458. Besides it includes usually a mem- brane bone, the interparietal, which occurs only in mammals. This is, strictly speaking, a paired bone, arising in the angle between the parietals and the supraoccipital and fusing with the latter. In front of it lie, in the roof of the cranium, as in other vertebrates, the parietals (fused with the interparietals in many ruminants and rodents), the frontals and nasals, the lacrimals being always associated with them. In the floor of the cranium the sphenoid bone hes in front of the basioccipital portion of the occipital. In many mammals this consists of an anterior and a posterior portion throughout life; in man this condition occurs at least in the em- bryo. Each of these parts in development consists of three elements, the posterior with the basisphenoid as the body, and the paired alisphenoids (greater wings); the anterior is similarly composed of the presphenoid and the paired orbitosphenoids (lesser wings) (fig. 518, Spb, Ps, Als, Ors). In front of the sphenoid lies the ethmoid, Eth, likewise formed from three parts, the mesethmoid, which forms a partition between the two. 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 Hertwig, Richard, 1850-1937; Kingsley, J. S. (John Sterling), 1854-1929, ed. and tr. New York, H. Holt
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
