In Victoria, South Australia, and the N.W. of Tasmania, as well as in New Zealand, Cainozoic marine beds are well developed, and contain an extensive bivalved molluscan fauna. Of these fossils only a few common and striking examples can here be noticed, on account of the limits of the present work. The commonest genera are:--_Ostrea_, _Placunanomia_, _Dimya_, _Spondylus_, _Lima_, _Pecten_, _Arca_, _Barbatia_, _Plagiarca_, _Cucullaea_, _Glycimeris_, _Limopsis_, _Nucula_, _Leda_, _Trigonia_, _Cardita_, _Cuna_, _Crassatellites_, _Cardium_, _Protocardium_, _Chama_, _Meretrix_, _Venus_ (_Chione_), _Dosinea_, _Gari_, _Mactra_, _Corbula_, _Lucina_, _Tellina_, _Semele_ and _Myodora_. [Illustration: =Fig. 95--CAINOZOIC BIVALVES.= A--Dimya dissimilis, Tate. Balcombian. Victoria B--Spondylus pseudoradula, McCoy. Balcombian. Victoria C--Pecten polymorphoides, Zittel. Janjukian. South Australia D--Leda vagans, Tate. Janjukian. South Australia E--Modiola praerupta, Pritchard. Balcombian. Victoria ] =Persistent Species.--= To mention a few species of persistent range, from Balcombian to Kalimnan, we may cite the following from the Cainozoic of southern Australia:--_Dimya dissimilis_ (Fig. 95 A), _Spondylus pseudoradula_ (Fig. 95 B), _Lima (Limatula) jeffreysiana_, _Pecten polymorphoides_ (found also in the Oamaru Series, New Zealand) (Fig. 95 C), _Amusium zitteli_ (found also in both the Waimangaroa and Oamaru Series of New Zealand), _Barbatia celleporacea_, _Cucullaea corioensis_, _Limopsis maccoyi_, _Nucula tenisoni_, _Leda vagans_ (Fig. 95 D), _Corbula ephamilla_ and _Myodora tenuilirata_. =Balcombian Bivalves.--= On the other hand, many species have a restricted range, and these are invaluable for purposes of stratigraphical correlation. For example, in the Balcombian we have _Modiola praerupta_ (Fig. 95 E), _Modiolaria balcombei_, _Cuna regularis_, _Cardium cuculloides_, _Cryptodon mactraeformis_, _Verticordia pectinata_ and _V. excavata_. [Illustration: =Fig. 96--CAINOZOIC BIVALVES.= A--Modiola pueblensis, Pritchard. Janjukian. Victoria B--Cardita tasmanica, Tate. Janjukian. Tasmania C--Lucina planatella, Tate. Janjukian. Tasmania D--Ostrea manubriata, Tate. Kalimnan. Victoria E--Limopsis beaumariensis, Chap. Kalimnan. Victoria F--Venus (Chione) subroborata, Tate sp. Kalimnan. Victoria ] =Janjukian Bivalves.--= In the Janjukian Series restricted forms of bivalves are exceptionally numerous, amongst them being:--_Dimya sigillata_, _Plicatula ramulosa_, _Lima polynema_, _Pecten praecursor_, _P. eyrei_, _P. gambierensis_, _Pinna cordata_, _Modiola pueblensis_ (Fig. 96 A), _Arca dissimilis_, _Limopsis multiradiata_, _L. insolita_, _Leda leptorhyncha_, _L. crebrecostata_, _Cardita maudensis_, _C. tasmanica_ (Fig. 96 B), _Cuna radiata_, _Lepton crassum_, _Cardium pseudomagnum_, _Venus (Chione) multitaeniata_, _Solenocurtus legrandi_, _Lucina planatella_ (Fig. 96 C), _Tellina porrecta_ and _Myodora lamellata_.