. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates -- Anatomy. 50 COMPARATIVE MORPHOLOGY OF VERTEBRATES. the rib behind and strengthening the thorax. In the chelonia the ribs are confined to the dorsal side of the body and are fused to the costal plates (dermal skeleton) to form the carapace. Single- and double- headed ribs often occur in the same individual of various groups, and in the mammals the capitular head, instead of articulating with a distinct parapophysis, may rest in a socket formed by two successive FIG. 54.—Sacral vertebrae, ribs and pelvis of Tr
. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates -- Anatomy. 50 COMPARATIVE MORPHOLOGY OF VERTEBRATES. the rib behind and strengthening the thorax. In the chelonia the ribs are confined to the dorsal side of the body and are fused to the costal plates (dermal skeleton) to form the carapace. Single- and double- headed ribs often occur in the same individual of various groups, and in the mammals the capitular head, instead of articulating with a distinct parapophysis, may rest in a socket formed by two successive FIG. 54.—Sacral vertebrae, ribs and pelvis of Trionyx, obliquely from below. /, head and rochanter of femur; il, ilium; is, ischium; p, pubis; sr, sacral ribs; sv, sacral vertebras. The pelvis is never directly united to the sacrum, but sacral ribs intervene. These are distinct in the reptiles (fig. 54), but are fused to the transverse processes in other groups. THE STERNUM (BREASTBONE). The sternum includes the skeletal parts on the ventral side of the body, which are closely connected with the shoulder girdle and, except in the amphibia, with the ribs. The fact that it occurs only in verte- brates with legs (it is lacking in snakes and cascilians) shows that it has arisen in adaptation to terrestrial locomotion. In man it consists of three parts, a manubrium in front, a middle piece (gladiolus), and a xiphoid (ensiform) process behind, and these terms have been car- ried into other groups. In development the sternum arises in mammals by the formation of a longi- tudinal bar of cartilage in the linea alba on either side, ventral (medial) to the ends. 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 Kingsley, J. S. (John Sterling), 1854-1929. Philadelphia, P. Blakiston's son & co.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1912
