THE 



GEOLOGICAL MAGAZINE 



NEW SERIES. DECADE VI. VOL. I. 



No. XI.— NOVEMBER, 1914. 



CD:RX<3rXisr j^jL. .a.i?,tici-.e;s. 



I. — Notes on new or imperfectly known Chalk Polyzoa. 

 By K. M. Brydone, B.A., F.G.S. 

 (Continued from the August Number, ^j. 347.) 

 (PLATE XXXV.) 



A SMALL group of English Ilemhraniporce is stronglj- characterized 

 by the possession of interstitial avicularia having one end raised 

 into a smooth hood. No described species seems to possess such 

 avicularia, except perhaps the form figured by d'Orbigny as 

 Memhranipora concatenata} 



Membranipora cuculligera, sp. nov. (Tl. XXXV, Figs. 1,2.) 



Zoarium unilaminate, adherent. 



Zocecia fairly large, very slightly pyriform, areas oval, average 

 lengtli 'b to "6 mm., breadth "oS to '4 mm.; side walls fairly thick, 

 slightly overarching. 



Ocecia occurring freely, small, rather shortly globular, with slightly 

 concave free edges lying well back from the margin of the area, the 

 side wall of which is very thin beneath them (Fig. 2). 



Avicularia only of the type characteristic of the group, from 

 one-third to one-half the area of the surrounding zooecia ; the lower 

 part is pyriform and embraces the lower half of the aperture in 

 a horizontal plane; the upper part is raised as a hood, the free edge 

 of which rises at a steep angle and is marked off by a shallow furrow ; 

 they are fragile, but even badly damaged specimens generally suggest 

 their nature at once. 



This species is known only in the zone of 11. cor-anguinum in 

 Hants and Kent, where it occurs regularly. 



Membranipora vestigialis, sp. nov. (PI. XXXV, Figs. 3, 4.) 



Zoarium unilaminate, adherent. 



Zooecia elliptical, wide in the middle, but tapering a good deal at 

 the ends, with very low and very thin side walls looking like mere 

 traces of a more robust form ; average length of area "45 to -6 mm., 

 breadth -3 to "So mm. 



Ooecia numerous and fairly robust, small, helmet-shaped, but slightly 

 rectangular in ground plan, the free edge coinciding with the outline 

 of the area. 



1 Pal. Cret. Fran?., tome v, pi. 729, fig. 6. 



DECADE VI. — VOL. I.— NO. XI. 31 



