. Carnegie Institution of Washington publication. . Figs. 668 and 669.—Axestemys byssina. Xj. 668. Plastron. Xiphiplastron of type; hypoplastron from No. 1034 A. M. N. H. 669. Part of nuchal and left first costal. the bone articulated with the first neural. The direction of the proximal border shows that the anterior neural was broader at the anterior end than behind. The hinder border of the costal is jagged, for sutural union with the next costal. The rib-end of the first costal plate seems to have been overlapt by the outer end of the nuchal. This species was a large one. The free borders o
. Carnegie Institution of Washington publication. . Figs. 668 and 669.—Axestemys byssina. Xj. 668. Plastron. Xiphiplastron of type; hypoplastron from No. 1034 A. M. N. H. 669. Part of nuchal and left first costal. the bone articulated with the first neural. The direction of the proximal border shows that the anterior neural was broader at the anterior end than behind. The hinder border of the costal is jagged, for sutural union with the next costal. The rib-end of the first costal plate seems to have been overlapt by the outer end of the nuchal. This species was a large one. The free borders of the costals were beveled off very ob- liquely to a sharp edge and on this beveled surface decussating bony fibers, like those of the plastron, are seen in abundance. How far the free portion of the ribs extended beyond the border of the carapace can not be determined, but the distance must have been considerable. The sculpture of the costals resembled that of the nuchal; but, in places at least, the pits are larger and the ridges sharper. The walls slope away gradually toward the bottom of the pits. There is little or no tendency toward the arrangement of the pits in rows. There appears to be sufficient reason for believing that the plastral and the carapacial bones here described belonged to the same individual. Genus AMYDA Oken. present. One or more of may be separated by the Carapace normally with H pairs of costal plates. No preneura the posterior pans of costals may be in contact on the midline, or a neurals. Young in living forms with numerous longitudinal dorsal dermal ridges or series of tubercles. Type: Trionyx euphraticus 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 Carnegie Institution of Washington. Washington, Carnegie Institution of Washington
Size: 1820px × 1373px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorcarnegie, bookcentury1900, bookdecade1900, bookyear1908
