Species of the genera (?) Membranipora and (?) Lepralia, belonging to the Cheilostomata, have been described from the Lower Cretaceous of the Darling River, New South Wales, and Wollumbilla, Queensland, respectively.
Cainozoic Polyzoa.—
A very large number of genera of the Polyzoa have been described from the Tertiary strata of South Australia and Victoria. Some of the principal of these are Crisia, Idmonea, Stomatopora, Lichenopora, Hornera, Entalophora and Heteropora of the order Cyclostomata; and Catenicella, Cellaria, Membranipora, Lunulites, Selenaria, Macropora, Tessarodoma, Adeona, Lepralia, Bipora, Smittia, Porina, Cellepora and Retepora of the order Cheilostomata. Many of these genera, and not a few Australian species, are found also in the Cainozoic or Tertiary beds of Orakei Bay, New Zealand ([Fig. 84]).
BRACHIOPODA (Lamp-shells).
Brachiopods: Their Structure.—
These are marine animals, and are enclosed in a bivalved shell. They differ, however, from true bivalves (Pelecypoda) in having the shell on the back and front of the body, instead of on each side as in the bivalved mollusca. Each valve is equilateral, but the valves differ from one another in that one is larger and generally serves to attach the animal to rocks and other objects of support by a stalk or pedicle. Thus the larger valve is called the pedicle valve and the smaller, on account of its bearing the calcareous supports for the brachia or arms, the brachial valve. Generally speaking, the shell of the valve is penetrated by numerous canals, which give the shell a punctate appearance. Some brachiopod shells, as Atrypa and Rhynchonella, are, however, devoid of these.
Fig. 85—LOWER PALAEOZOIC BRACHIOPODS.
