300 



hinge is narrow for the size of the shell, and is deeply and hroadly 

 channelled in the middle ; muscular impression large and deep. 



The author compares it with some varieties of the living 

 0. edulis, Linnteus. 



Dimensions. — Height 172 mm. ; length 125 mm.; thickness of 

 left valve 47 mm. 



Form, and Loc. — Eocene (?) : Bairnsdale, Gippsland, Victoria. 



L. 5146. Left valve of the adult. Purchased. 



Ostrea arenicola, Tate. 



1886. Ostrea arenicola, Tate, Trans. Eoy. Soc. South Aust. vol. viii. 

 p. 97, pi. X. fig. 6. 



Shell large, elongately ovate, slightly ohlique, and produced 

 anteriorly ; umbones depressed, bent forward. Left valve usually 

 attached in the neighbourhood of the umbo ; radial ridges irregular, 

 broad, and undulating throughout their length ; lamellar plates 

 frequent. Eight valve flat or but slightly concave, except by 

 contraction in senile individuals ; growth-lines prominent. 



It differs from the living 0. angasi in having the umbones 

 depressed and directed forward, whilst the left valve is more 

 costate. 



Dimensions. — Height 119 mm.; length 95 mm. 



Form, and Loc. — Eocene (?) : South Australia. 



42698. Double-valved specimen, the scar of attachment being 

 small ; from near Adelaide. Presented hy M. Marshall, Esq. 



L. 10523. Examples of the senile stage, larger than that 

 indicated by Professor Tate ; from Willunga, near Adelaide. 



R. T. L. Brown Coll. 



Ostrea manubriata, Tate. 



1887. Ostrea manubriata, Tate, Trans. Roy. Soc. South Aust. vol. is. p. 184, 



pi. xix. fig. 10. 

 1889. Ostrea manubriata, Dennant, id. vol. si. p. 49. 



This species is more elongate than either of the preceding, and 

 the left valve is a great deal larger than the right ; hinge 

 frequently one-third the length of the shell in the left valve, 



