434 R. M. Brydone—New Chalk Polyzoa. 
Mermpranrpora FONTEIA, sp. nov. (Pl. XVIII, Figs. 3 and 4.) 
Zoarium unilaminate, adherent. 
Zowecia fairly large, with a tendency to angular sides, bluntly 
pyriporiform when occurring in established lines, and acutely so 
when initiating new lines; areas typically oval, with the upper end 
generally flattened and often indented, average length ‘5 mm., breadth 
-30 mm. 
Owcia globular, rather elongated, with a deeply concave free edge ; 
aperture high and narrow. ; 
Avicularia sub-vicarious, initiating new rows of zocecia, mandibular 
in type, much inflated laterally. : 
MermBRANIPORA CUBITALIS, sp. nov. (Pl. XVIII, Fig. 5.) 
Zoarium unilaminate, adherent. ; 
Zowcia sub-pyriporiform, fairly large, very variable in dimensions, 
unusually wide, sometimes much wider than long, with sharply 
angular elbow-like sides; areas widely oval, flattened at the upper 
. end, average length -45 mm., breadth -4mm., front walls almost flat. 
Owcia abundant, short wide inconspicuous swellings, the free edges 
of which coincide with the areal outline. 
Avicularia vicarious, of the ‘Lesueurt’ type, but unusually wide 
and short, and with the nodal points close to the upper end of the 
area; they are so nearly identical in size with the zocecia and the 
nodal points impinge so slightly on the areal outline that it is 
very difficult to pick them out (there are three in Fig. 5), but a side 
light will catch the upturned edge of the infold of the side wall and 
make it stand out against the deep-lying internal front wall. 
Mempranirora FuLGoRA, sp.nov. (Pl. XVIII, Fig. 6.) 
Zoartum unilaminate, adherent. 
Zoecia large, very shallow, with very thin side walls and no front 
walls at all, which gives them avery primitive aspect; average length 
of areas ‘65 mm., breadth ‘5 mm.; at the foot of the area there occurs 
very regularly a crescent-shaped cavity in the floor, round which the 
floor is slightly raised and which may be ocecial ; the side walls tend 
to expand at the bottom, and the curved part is here and there 
pierced by pores, which probably occur regularly though only visible 
irregularly. 
There are no signs of external occia. 
Avicularia sub-vicarious, initiating new rows of zocecia, of the 
hour-glass type, but hardly expanding at all below the contracted 
region, while above the contracted region there is a widely expanded 
part taking up about half the total length; the front wall is reduced 
to a minimum, and they are practically all side wall and area; in the 
lower two-fifths of the area the floor is at a lower leyel than in the 
upper three-fifths, and from the centre of the edge of the upper floor 
a narrow tongue runs down to the lower floor; remains of a crossbar 
occur at the lower end of the constricted region. This species has 
an interesting general resemblance to If. faustina (ante, p. 337). 
