Art. IV. — Contributions to the Palaeontology of the 

 Older Tertiary of Victoria. 



Lamellibranchs. — Part II. 



By G. B. PRITCHARD, 



Lectvirer on Geology, etc., Working Men's College, Melbourne. 



("With Plates II. and III.). 



[Eead 16th May, 1901]. 



The present paper include.s a few interesting species from some 

 of our more important sections, but it is with regret that I am at 

 present unable to include some promised remarks on some of our 

 common Crassatellites and Chiones, there is a good deal of 

 material at present in hand, but I do not yet feel confident 

 enough on certain details to express a definite opinion. 



Ostpea hyotis, Linnaeus. 

 1758. Mytilus hyotis, Linnaeus. Syst. Nat., ed. 10, 



p. 707. 

 1899. Ostrea hyotidoidea, Tate. T.R.S. S.A., vol. xxiii., 

 pt. ii., p. 268. 

 Locality. — Moriiington Clays. 



Observations. — This shell was originally determined by Pro- 

 fessor Tate as O. hyotis, Linnaeus, and this identification has 

 evidently been accepted by Mr. Harris, of the British Museum, 

 in his Catalogue of Australasian Tertiary Mollusca (see p. 299), 

 as he remarks that "The general contour of the shell (which, 

 however, is extremely variable in regard to details) is that of the 

 living O. hyotis, and it has the characteristic foliaceous scales of 

 that species." Now, Professor Tate, as indicated above, regards 

 our species as distinct, and notes the following points for the 

 distinction: "The fossil species is more depressed, more irregular 

 in outline, the radial ridges less elevated and obtuse, whilst the 

 foliaceous scales very rarely develop into tubular spines.'' Not 

 having examples of the living species, I am not at present in a 

 position to express a definite opinion. 



