. Bulletin of the Natural Histort Museum. Geology series. JURASSIC BRYOZOANS FROM BALTOW, POLAND 97 ;*Â¥. /' W^*. ^ c Figs 19-22 Jurassic bereniciform cyclostomes with transversely-ridged colonies similar to Hyporosnpora halwvensis sp. nov. 19-20, Hyporosopora enstonensis (Pitt & Thomas, 1969), BMNH D51451, holotype, Bathonian, Hampen Marly Beds, , Oxfordshire, England; 19, x 13; 20, gonozooid, x 80. 21-22. Plagioecia riigosa (d'Orbigny, 1853), BMNH BZ51, Lower Kimmeridgian, St Jean des Sables, near La Rochelle, Charente Maritime, France; 21, small colony with prominent tran
. Bulletin of the Natural Histort Museum. Geology series. JURASSIC BRYOZOANS FROM BALTOW, POLAND 97 ;*Â¥. /' W^*. ^ c Figs 19-22 Jurassic bereniciform cyclostomes with transversely-ridged colonies similar to Hyporosnpora halwvensis sp. nov. 19-20, Hyporosopora enstonensis (Pitt & Thomas, 1969), BMNH D51451, holotype, Bathonian, Hampen Marly Beds, , Oxfordshire, England; 19, x 13; 20, gonozooid, x 80. 21-22. Plagioecia riigosa (d'Orbigny, 1853), BMNH BZ51, Lower Kimmeridgian, St Jean des Sables, near La Rochelle, Charente Maritime, France; 21, small colony with prominent transverse ridges, x 14; 22, gonozooid in a larger colony encrusting the same substrate, x 30. 1981). H. enstonensis (Pitt & Thomas, 1969) from the Bathonian of Oxfordshire (Figs 19-20), and Mesenteripora undulata (Michelin, 1845) from the Bathonian of Normandy (revised by Walter, 1970). A â 'ew post-Jurassic cyclostomes also possess transversely ridged colo- lies ( Plagioecia plicata (Canu) from the Eocene of France, see Buge, 1979a; Berenicea iindata Canu & Bassler, 1920 from Eocene of the USA), but this morphology seems to be proportionally less :ommon than in the Jurassic. Compared with Hyporosopora baltovensis, the gonozooid in ^lagioecia rugosa is broader and is penetrated by autozooidal apertures (Fig. 22). In other respects, however, the two species are i/ery similar, although the transverse ridges tend to be more strongly developed in P. rugosa (Fig. 21). Walter (1970: 218) considered P. rugosa to be a junior synonym of Cellepora orhiculata Goldfuss, 1826 from the Oxfordian of Streitburg in Germany. The syntypes Universitat Bonn, Goldfuss Collection 104) of C. orhiculata have been studied but are poorly-preserved, lack diagnostic gonozooids, and probably represent more than one species. C. orhiculata is probably better discarded. Hyporosopora portlandica has narrower gonozooids than H. haltovensis, and autozooidal apertures which are more widely- spaced and
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