PLETHOPOEA, SPAESICYTIS, POLTPHYMA. 
231 
TOREPEESENTED SPECIES. 
1. cervicornis (d’Orbigny), 1850. 
Syx. Monticulipora cervicornis, d’Orbigny, 1850. Prod. Pal. vol. ii. p. 279. 
Plethopora ,, d’Orbigny, 1854. Bry. Cret. p. 1045, pi. 799, 
figs. 4, 5. 
Sparsicytis ,, Filliozat, 1908. Brj'. Cret. Vendome : Bull. 
Soc. geol. France, ser. 4, vol. vii. p. 398. 
Char. — Apertures collected along conspicuous transverse crests. 
Distrib. — Senonian — Coniacian : Tours, Indre -et- Loire. ^ 
2. concava, Eilliozat, 1908. 
Syx. Sparsicytis concava, Filliozat, 1908. Bry. Cret. Vendome : Bull. Soc. 
geol. France, ser. 4, vol. vii. p. 399, pi. xiv. fig. 5. 
Char. — Zoarium with irregularly bent stems, 2 mm. in diameter. The lateral tufts 
are elongated transversely, being about twice as long horizontally as they are wide. 
Distrib. — Senonian — Coniacian: Vendome (Zone of Crania ignabergensis), 
Loir-et-Cher. 
POLYPHYMA, Hamm, 1881. 
[Bry. mastr. Ob. -Sen. i., Cycl. p. 38.1 
Diagnosis. 
Zonatulidge with a nodular, multilamellar zoarium, with a knob- 
bearing upper surface. The zooecia are short, unequal in size, 
' and arranged in round and somewhat knob-like, raised groups. 
The apertures are largest and quincuncially arranged in the 
middle of the knobs, and they gradually become smaller 
towards the sides. 
Type Species. 
Polyphyma hulhosa, Hamm. Maastrichtian : Maastricht. 
Affinities. 
Hamm places this genus in his Cerioporina, after the genus 
Zonatula. The zooecia appear to be dimorphic. The multilamellar 
structure is conspicuous. It may be regarded as a multilamellar 
Plethopora. 
HHEEPRESENTED SPECIES, 
bulbosa, Hamm, 1881. 
Syn. Polyphyma bulbosa, Hamm, 1881. Bry. mastr. Ob. -Sen. i., Cycl. p. 38. 
Char. — Zoarium simple and like a flattened tuber. Apertures in the middles of 
the knobs, quincuncial, and separated by very thick walls. Zooecia very 
short and wide. 
Distrib. — Senonian — Maastrichtian : Maastricht. 
^ The locality given by d’Orbigny in 1850 was Royan, a Maastrichtian horizon, 
but it was not repeated by d’Orbigny in 1854. 
