A PECULIAR PELVIC ATTACHMENT IN NECTURUS MACULATUS

Abstract

While studying the vertebral column of Necturus maculatus, in the regular class work, I found in my specimens a peculiar form of pelvic attachment which seems remarkable enough to mention. The pelvis was attached to the eighteenth vertebra and, in ad dition, there were two rudimentary ribs on the nineteenth. There was nothing strange about the twentieth but on the twenty-first there was one half of a h@ma1 spine, that of the right side, the first complete ha@mal arch being on the twenty-second. For comparison in order to show its anomalous character, it is necessary to give the statistics concerning the conditions as reported hitherto. F. Smith, †? oo, and Wilder, †? 02, have summa rized the results hitherto reported, including the papers of Parker, †? 96, Bumpus, †? 97, and Waite, †? 97. In one hundred and fourteen specimens tabulated by Smith, the sacral vertebra was the nineteenth in eighty-one cases, the twentieth in sixteen and the twenty-first in one, this latter being the most posterior position ever recorded. In twelve cases the pelvis was oblique and of these three made use of the eighteenth on one side. In four cases there were three sacral ribs, that is, two upon one side and in one of these, figured by Smith on page 638, the ribs involved were the eighteenth on the right and the eighteenth and the nineteenth on the left. Thus in Smith's one hundred and fourteen cases, four involved the eighteenth ver tebra but all were asymmetrical. The one which approached nearest my specimen is the one figured by Smith, where there was a ligamentous connection between the rib rudiment on the nineteenth and the sacrum, and as my specimen had been maccr ated before I examined it, I cannot tell whether there was such a connection or not. As Wilder has used the same authors for his summary as has Smith, it is unnecessary to give his report.