In the September Number of the Geological Magazine, 1890, I offered some notes on certain Triassic Estheriœ of North America and Bavaria, and on an Estheria from the Purbeck strata of Wiltshire. An interesting example of E. membranacea from the Old Red of Orkney was figured, but not described. We have now the Rev. W. R. Andrews's other Purbeck Estheria, referred to at p. 389, ready for description; another Triassic Estheria from Pennsylvania; and some most interesting specimens of the rare Estheriella, instituted as a subgenus by the late Professor Dr. Ch. Ernst Weiss.