Recently a large series of the most important species of Platystoma and Strophostylus was examined and the matrix carefully removed from the apertural portions of many of the shells. The structural features disclosed in the various forms show a relationship between the two established genera that was long suspected. The two types are now regarded as identical.
Proceedings of the Iowa Academy of Sciences
©1890 Iowa Academy of Science, Inc.
Keyes, Charles R.
"Evolution of Strophostylus,"
Proceedings of the Iowa Academy of Science, 1(Pt. 2), 25-26.
Available at: https://scholarworks.uni.edu/pias/vol1/iss2/12