I.—Notes on new or imperfectly known Chalk Polyzoa

Extract

Cheilostomatous Polyzoa are anything but common in the Chalk exposed on the Norfolk coast between Cromer and Weybourne, and which I will call the Weybourne Chalk as it is best exposed in the Weybourne half of the area. It was only quite recently that I realized that the gradual accumulation of material had produced a sufficient volume to give some idea of the general nature of the fauna. The precise position of this chalk in the zone of B. mucronata cannot be fixed on physical data, but the Survey view that it is only a little way below the Trimingham Chalk is highly probable. It is therefore rather remarkable to find that the Membraniporæ include several new species, in addition to M. flacilla (ante, p. 338), which are unknown so far at Trimingham. It will be interesting to see if these, which I proceed to describe, prove to be characteristic of any definite range of chalk in the Norfolk Senonian. They must all be described as scarce at Weybourne.