Discovery reports (1947) Discovery reports discoveryreports23inst Year: 1947 THE SOUTHERN BOTTLENOSED WHALE 23 the maxillary crests. These in H. rostratus originate anteriorly approximately equidistantly between rostrum tip and antorbital notch, and ascend in a slope which varies according to age to a summit which overtops the skull vertex in all but the most juvenile specimens. Posterior to the summit there is a decline in level which is generally more abrupt than the anterior slope, the maxillar}' bone attaining normal thickness again before it ascends posteriorly in contact with the verti
Discovery reports (1947) Discovery reports discoveryreports23inst Year: 1947 THE SOUTHERN BOTTLENOSED WHALE 23 the maxillary crests. These in H. rostratus originate anteriorly approximately equidistantly between rostrum tip and antorbital notch, and ascend in a slope which varies according to age to a summit which overtops the skull vertex in all but the most juvenile specimens. Posterior to the summit there is a decline in level which is generally more abrupt than the anterior slope, the maxillar}' bone attaining normal thickness again before it ascends posteriorly in contact with the vertical portion of the frontal. The crests in H. planifrons originate anteriorly about two-thirds from the anterior end of the distance between rostral tip and antorbital notch. The slope is gradual to a low summit above the antorbital notch, and the decline posteriorly is equally gradual so that there is no horizontal thin portion of maxillary before it rises vertically in contact with the frontal in the occipital crest. In the Discovery specimen the maxillary crests are less massive than in the South Australian specimen. It may be that the difference is associated with sex, but it may equally v/ell be due to difference in age.
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