98 R. M. Brydone — Neio Chalk Polyzoa. 



MOLLIA LAMINARIA, Sp. nOV. (PI. IV, FigS. 5-7.) 



Zoarium unilaminate, adherent, consisting of a thin uneven crust 

 out of which the zooecia rise more or less disconnectedly. 



Zooecia convex, quite smooth, very small, average length -3 to 

 •32 mm., generallv in contact with others on one or more sides, but 

 sometimes wholly isolated ; they show a distinct tendency to linear 

 arrangement ; apertures keyhole-shaped and rather short for that type. 



Ocecia very large but inconspicuous, globose with a very sliort 

 concave free edge which sliglitly impinges on the zooecial aperture. 



Avicularta perhaps represented by the tiny aborted zooecia which 

 are scattered freely about the zoarium. 



Very abundant at Trimingham and not uncommon in the Weyhourne 

 Chalk. I place it temporarily in the genus Mollia on account of its 

 apparent relationship to M. guttata, d'Orb.^ 



It might be a specimen of this form which was figured as Flustra 

 iitricularis by Samuel Woodward.^ 



HOMALOSTEGA MAEGINXTLA, Sp. UOV. (PI. IV, FigS. 8, 9.) 



Zoarium unilaminate, adherent. 



Zocecia of moderate size, average length "5 mm., with circular side 

 walls bent strongly inwards, which at the foot form a distinct thin 

 rim raised slightly above the smooth, flatly arched front wall, but 

 gradually blend into it towards the head ; apertures small and 

 superficially semicircular, but apparently contracting progressively 

 downwards into a narrow crescent ; fairly large pores occur somewhat 

 irregularly in the side walls when exposed to view. 



Ocecia and avicularia unknown. 



This species occurs very sparingly in the zone of M. cor-testudi- 

 narium at Seaford and Dover. It seems to have near relations in the 

 early French Chalk, such as Reptescharellina oceani, D'Orb.^ 



Pig. 8 is given on account of the faint appearance of radiating 

 furrows (? Cribrilinid ancestry) presented by some of the zooecia. 



HoMALOSTEGA NITESCENS, Sp. nOV. (PL IV, FigS. 10-12.) 



Zoarium unilaminate, adherent, noticeably bright. 



Zooicia of medium size, average length '6 to "65 mm. ; front walls 

 flatly arched, slightly below rather sharply defined side walls just 

 below the aperture but rising flush with and merging into them 

 towards the foot; in the upper part of the zooecium the side walls 

 have a strong tendency to bulge out low down, occasionally producing 

 a sort of external front wall with quite an abrupt margin ; apertures 

 small, high, and narrow with a straight lower lip, upwards from 

 which the almost straight sides converge very gradually until they 

 are ended by a very flat arch ; paired, circular, flat, wide, perforated 

 spine bases occur on the margin at about half the height, and impinge 

 slightly on the aperture ; above them come a pair of pores situate 

 close to the margin just below the upper corners, and another pair 

 occur close together in the centre of the arch. 



1 Pal. Fran.?. Terr. Cret., torn, v, p. 389, pi. 712, figs. 1, 2. 



2 Geol. Norfolk, by Samuel Woodward, 1833, tab. iv, fig. 7. 

 2 Loc. cit., p. 454, pi. 605, figs. 14, 15. 



