A few instances will serve to illustrate this point. Thus there are two specimens labelled Placochalina pedunculata, var. mollis these upon examination proved to be (1) Chalina palmata and (2) Clathria tenuifibra. The first named consists of a series of flat lamelIae, which are intricately folded, and the specimen bears the manuscript name of Placochalina reticulata. The second form has been neatly perforated by a boring Isopod, and hence it is labelled Plaeoehalina porosa. Antheroehalina dura is represented by a specimen of the cake-shaped. Chalina globosa, and appears under the manuscript name of Suberochalina panis. The following cases will convey to the reader some idea of the difficulties met with, and also of the confusion revealed by the examination of this collection. I may here remark that the examples are not all regarded as types, although it is possible some of them may be portions of the actual type specimen.