It does not appear to the present writer that Rhoads has successfully maintained his proposition. He did not have at hand a sufficient number of skulls of the existing Atlantic walrus to present all the variations that occur in that species. Of course, the number of fossil specimens was very limited. In discussing Rhoads’s conclusion, it will be of advantage to consider a part of a skull which belongs to the Marsh collection in Yale University. This specimen consists of the anterior half of the skull, without the tusks and without the other teeth. It was found at Kitty Hawk, at the mouth of Albemarle Sound, just north of latitude 36°. It is thoroughly fossilized; and, having been found so far south, it may be safely regarded as having belonged to the species which inhabited the New Jersey coast during the Pleistocene.
For purposes of comparison, such measurements are here given as can be obtained from the skull; likewise the corresponding measurements of a specimen from Sable Island, No. 199528 of the U. S. National Museum, and of another, No. 22014 of the National Museum, brought from Ungava Bay. Unfortunately, the basilar length of the fossil can not be determined, nor the width of the mastoids.
_Measurements of skulls of walruses, in millimeters._
┌─────────────────────────────────────────────┬───────┬───────┬───────┐ │ │ Kitty │ Sable │Ungava │ │ │ Hawk. │Island.│ Bay. │ ├─────────────────────────────────────────────┼───────┼───────┼───────┤ │From front of premaxillæ to rear of vomer │ 183│ 167│ 205│ │From front of tusk to optic foramen │ 188│ 177│ 195│ │From oral border of premaxilla to upper │ │ │ │ │ border of nasal opening │ 110│ 96│ 100│ │Greatest width across maxillæ │ 160│ 136│ 177│ │Least width at front of orbits │ 105│ 106│ 146│ │Least width at temporal fossæ │ 75│ 62│ 70│ │Width between the sockets for tusks │ 75│ 75│ 85│ │Length of row of teeth │ 82│ 60│ 83│ │Space between incisors │ 40│ 36│ 32│ │Space between last molars │ 62│ 60│ 53│ │Long diameter of tusk at base │ 34│ 26│ 38│ └─────────────────────────────────────────────┴───────┴───────┴───────┘
The nasal bones of the fossil are so thoroughly consolidated with each other and with the adjoining bones that their dimensions can not be determined. There is no reason, however, for supposing that the length was greater than 70 mm.