Abnormalities in the Uterine Young of Campeloma rufum, a Fresh-Water Snail

Abstract

In the study of our fresh-water snails, work on the developmental forms has been very incomplete. This is true of Campeloma, one of the genera of the family Viviparidae found in the eastern United States; and it is particularly true of the species C. rufum regarding the uterine development of which very little is known. In view of this fact a study of the uterine development especially of abnormal forms was undertaken. All of the collections have been made at Homer Park, Illinois, in the Salt Fork branch of the Vermilion River, where C. rufum is the only species of Campeloma and where it occurs in relatively large numbers. During the period from September 1933 to May 1934, 274 individuals were collected in eight different samples, varying in number from 25 to 66 per sample. The writer is indebted to Dr. H. J. Van Cleave, of the University of Illinois, whose helpful suggestions and encouragement have made this study possible. Likewise to Mr. Frank C. Baker, who determined the specimens, and to John Mizelle, William Van Deventer, and Philip Van Cleave who helped in the collection of materials.