108 
OSCUMPORID.55. 
be regarded as three or more Bicnvea, growing in a vertical series. D’Orbigny 
included in this species a flat discoid zoarium with a short lateral stem like 
Orbitulipora petiolus, Greg.,' from the British Eocene. M. Pergens in 1886 
included the species as specifically identical with B. vrnula. lie subsequently 
receded to the perhaps unnecessarily extreme position of separating them 
generically. 
3. pergensi, Gregory, 1907. 
Syn. Madiopora urn ula, pars, k 1887. Brv. gar. Faxe : Ann. 
Soc. raal. Belg. vol. xxi. p. 224, pi. ix. tigs. 1-5 ; 
pi. X. fig. 6. 
Lichenopora ,, ,, Ilennig, 1894.^ Brv. Sver. Krit. ii., Cycl. : 
Lunds Univ. Arsskrift, vol.xxx., Acta Physiogr. 
Xo. viii. p. 34. 
Bicavca pcrgensi, Gregory, 1907. Kotif. Brv. Isle of Wight : Geol. Mag. 
dec. 5, vol. iv. p. 443. 
Diagnosis. — Zoarium with the stem, when present, covered with a|>ertures. The 
apertures on the body open on vertical ridges, which project slightly above the 
central part of the body. The apertures on these ridges are biserial to quadri- 
serial, and are quincuncial in arrangement. The ridges may project at their 
upper corner into spikes. The form is very variable ; it is irregular, and the 
zoarium sessile, with the ridges projecting upward into spikes, in var. sessiHs, 
P. & M. The form is piriform in var. iuttrmedia, P. A' M. ; it has a cylindrical 
stem which expands rapidly to the Ixxlyof the zoarium in var. sfipitata, P. & M. 
Distrib. — Danian : Faxoe ; Annetorp, Sweden. 
Aff. — This variable species differs from the British Turonian species, B. rota- 
formis, Greg., by the convex base, perforate stem, and lesser development of 
the lateral ridges around the body of the zoarium. It differs from the French 
Maastrichtian species B. urmda (d’Orb.) by not having the vasiform head of 
that species; the form intermedia approaches to B. urnula, var. dilatnta, in 
this respect, but the apertures in B. pergensi are in vertical series down the 
sides of the body, and although these ridges may project upward as short 
spines, they do not form the high spines or erect keel-like plates of B. urnula. 
The var. stipitata, P. A M., as figured op. cit. pi. ix. fig. 1, is here selected 
as the type of the species. 
4. urnula (d’Orbigny), 1850. 
Syn. Fasciculipora urnula, d’Orbigny, 1850. Prod. Pal. vol. ii. p. 268. 
Bicavea ,, d’Orbigny, 1853. Bry. Cret. p. 956, pi. 776, figs. 1, 2. 
,, {Lichenopora) urnula, Eowe, 1908. Zones of Chalk. — V. Isle of 
Wight : Proc. Geol. Assoc, vol. xx. p. 302. 
Radiopora urnula, pars, Pergens & Meunier, 1887. Bry. gar. Faxe : 
Ann. Soc. mal. Belg. vol. xxi. p. 224. 
Lichenopora ,, Pergens, 1890. Eev. p. 383. 
Bicavea d’Orbigny, 1853. Bry. Cret. p. 956, pi. 776, figs. 3, 4. 
Multicrisina cupula, pars, Pergens & Meunier, 1887. Op. cit. pp. 224, 226. 
1 Gregory. Brit. Pal. Bry. : Trans. Zool. Soc. 1893, vol. xiii. p. 253, 
pi. xxxi. figs. 12-14. 
