A NEW TYPE OF THE NAYAD-GENUS FUSCONAIA. GROUP OF F. BARNESIANA LEA.
BY A. E. ORTMANN.
During the study of the nayad-fauna of the upper Tennessee, the present writer found that there exists, in this region, a peculiar type of shells, belonging to the genus Fusconaia, the various forms of which have been described previously under a great number of specific names, which, however, seem to belong all to one species. In addition, among material received from L. S. Frierson from the Ozark Mountains, a form was discovered which presented the same structure.
The oldest name for the upper Tennessee form is Unio barnesianus Lea. A more detailed account of its various phases is to be given elsewhere, and it suffices here to mention only those forms which belong here. According to obesity, I distinguish three local, or ecological races: