. Bulletin - United States National Museum. Science. A NEW WHALEBONE WHALE 19. Figure io.—Anterior view of axis, USNM 11976, of Peloceius calvertensis. Abbrs.: od., odontoid process; tr., transverse process. transverse process on each lateral face. Conversely, the atlases of all the Calvert Miocene odontocetes possess a prominent and often noticeably elongated or enlarged hyapophysial process and usually a fairly well developed lower (parapophysis) and a variably developed upper (diapophysis) transverse process. On the atlas (USNM 23059, pi. 3, fig. 5) of the referred specimen, the distance (1
. Bulletin - United States National Museum. Science. A NEW WHALEBONE WHALE 19. Figure io.—Anterior view of axis, USNM 11976, of Peloceius calvertensis. Abbrs.: od., odontoid process; tr., transverse process. transverse process on each lateral face. Conversely, the atlases of all the Calvert Miocene odontocetes possess a prominent and often noticeably elongated or enlarged hyapophysial process and usually a fairly well developed lower (parapophysis) and a variably developed upper (diapophysis) transverse process. On the atlas (USNM 23059, pi. 3, fig. 5) of the referred specimen, the distance (183 mm.) between the outer mar- gins of the anterior facets for articulation with the occipital condyles of the skull exceeds slightly the same measurement of the type atlas, yet the anteroposterior diameter (72 mm.) of the centrum is less. Both transverse processes of this referred atlas are eroded. The two posterior facets for articulation with the axis are slightly larger than those of the type atlas, but no hyapophysial process below the neural canal is developed as a distinct entity. The usual broad upward sloping surface for articulation with the odontoid process of the axis is present between the opposite large articular facets. Additional measurements of this referred atlas are as follows: Vertical diameter of axis, tip of neural spine to ventral face of centrum, 163-(- mm.; maximum vertical diameter of neural canal anteriorly, 80 mm.; maximum transverse diameter of neural canal, 57 mm.; maximum distance between outer ends of diapophyses, 142-|- mm.; and least anteroposterior diameter of right pedicle of neural arch, 54 mm. Axis: The axis (pi. 4, fig. 2) is solidly fused with the third cervical (pi. 4, fig. 7), not only between the centra but also between the post- and pre-metapophysial facets. The transverse diameter (388 mm.) of the axis (fig. 10) is greater than twice its vertical diameter (165 mm.). Each ventral transverse process is massive, elongated, dorsoventra
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