. Bulletin - United States National Museum. Science. diameter of the palatine is equivalent to about 17 (USNM 16570) to 20 percent (USNM 10677; fig. 83) of the length of the skull. The supraorbital processes of the frontals are incomplete on all skulls except the young specimen (USNM 10668). On one (USNM 10677), the outer portion of the right process is well preserved (pi. 65, fig. 4). The preorbital angle of this process is rounded and the postorbital is ex- tended backward to the end of the zygomatic process. On the young skull (fig. 84; USNM 10668) the channel for the optic ne
. Bulletin - United States National Museum. Science. diameter of the palatine is equivalent to about 17 (USNM 16570) to 20 percent (USNM 10677; fig. 83) of the length of the skull. The supraorbital processes of the frontals are incomplete on all skulls except the young specimen (USNM 10668). On one (USNM 10677), the outer portion of the right process is well preserved (pi. 65, fig. 4). The preorbital angle of this process is rounded and the postorbital is ex- tended backward to the end of the zygomatic process. On the young skull (fig. 84; USNM 10668) the channel for the optic nerve curves outward on the ventral surface of the supraorbital process of the frontal in the usual manner and increasing in width becomes widest at the orbital rim. Near. Figure 83.—Ventral view of skull, USNM 10677, oi Parietobalaena palmeri Kellogg, restored. For abbreviations, see figure 79. Figure 84.—Ventral view of skull (type), USNM 10668, of Parietobalaena palmeri Kellogg. For abbreviations, see figure 79. its origin this channel is located on the posterior surface of this process but twists downward to the ventral surface and then on its outward course is located behind the well- defined anterior wall. The ventral surface of the relatively narrow basioccipital is shallowly concave. On each side of this bone the lateral descending protuberance, although variable in shape pos- sibly attributable to age, is convex internally and over- lapped anteriorly by the vaginal process of the pterygoid. The basioccipital is so intimately fused with the basisphe- noid, even on the young skull (USNM 16838), that the sutural contact is obliterated. A narrow gap separates the alisphenoid and the presphenoid at least until physical maturity. Both the alisphenoid and the presphenoid are hidden from a ventral view by the overspreading ventral horizontal plate of the Please note that these images are extracted from scanned page images that may have been digitally en
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