THE 
GHOLOGICAL MAGAZINE 
NEWASERIES.) DECADE. Vi. VOLE, Ml. 
No. III.— MARCH, 1916. 
ORIGINAL ARTICLIEHS. 
EEO DOE 
I.—Nores ON NEW OR IMPERFECTLY KNOWN CHALK Potyzoas. 
By R. M. BRYDONE, F.G.S. 
(Continued from Decade VI, Vol. I, November, 1914, p. 483.) 
. PLATE VI. 
Mempranipora supacuminata, nov. (Pl. VI, Figs. 1, 2.) 
Zoarium unilaminate, always adherent. 
Zoecia separated by a distinct furrow, which passes into a deep 
crevice at the junction points, widely rounded below but tapering 
very considerably and almost to a point above, with areas of the same 
shape aud upright rounded side walls thickening considerably below, 
and often developing something of an internal front wall; average 
length of area -28mm., breadth -2mm., but marginal zoecia often 
run much larger. 
Owcia. No trace of any ocecium has been observed. 
Avicularia vicarious, humble examples of the ‘ Lesuewri-type’, as 
although strictly conformable in general structure they are only 
_a little larger than the surrounding zocecia; the node at which the 
very scanty front wall of the lower part splits into two is very 
inconspicuous, and the internal front wall of the upper part is 
relatively much wider than usual in proportion to the section of the 
_ area which it encloses. (I have always felt that it would be admissible 
to argue, on the species standing by itself, that these cells were not 
avicularia but ordinary zocecia with the addition of a wholly unroofed 
ocecial chamber; but I have never doubted myself that they were 
avicularia, and the recently discovered species which follows seems to 
put this beyond doubt.) 
This species is only known to me from the base of the zone of 
B. mucronata at Portsdown, where it is scarce but well distributed. 
‘Mempranreora Stupianpensis, noy. (Pl. VI, Figs. 3, 4.) 
Zoartium unilaminate, adherent. 
Zoecia piriform in outline (there being a considerable expanse of 
flat front wall below the area), and separated only by sutures; areas 
practically circular, average diameter °28 mm., but occasionally much 
larger ones occur. 
Oecia globular, of the water-bottle type, the constriction at the 
neck being slight but quite distinct, with a concave free edge falling 
‘somewhat back from the areal outline, small in proportion to the 
zocecia and with rather vague outlines, almost invariably present in 
the type-specimen. Beneath them the areal margin is low and very 
DECADE VI.—VOL. III.—NO. III. 7 
