The National Museum of Wales has not existed, as a working institution, long enough to have accumulated an extensive series of type and figured fossils, but since recent developments have rendered available for reference geological collections that were hitherto packed in store rooms, it is felt that the time is opportune for the publication of a note concerning the geological material which the Museum possesses, with special reference to the specimens that have been described or figured.

The section was visited by us in company with Dr. H. H. Thomas, of the Geological Survey, and F. A. Marr, Esq., in May, 1927.

Lough neagh is one of the numerous lakes possessing a few species, either identical with or differing but slightly from true marine forms living in the present seas. The idiots of Lough Neagh are the pollan, Coregonus pollan, and the shrimp, Mysis relicta (a near relative of the marine Mysis oculata). They have been described by Dr. R., F. Scharff and Professor W. Dakin and Miss M. Latarchie.

There are two well-preserved internal moulds in the collection which are very close indeed to the forms referred to Meek's species by Girty, but unfortunately nothing is known of the external ornamentation of the Peruvian specimens.