326 PINNA. 



Shell pearly, inequivalve, inequilateral, right valve flatter than 

 the left; hinge-line long, straight, with a cardinal tooth in the 

 young ; surface distantly, faintly striated. 



Dimensions. — Height 18 mm.; length 21mm. 



Form, and Log. — Eocene : Muddy Creek, Yictoria. 



L. 9843. Examples of both valves, of the neanic stage of 

 growth. Furchased. 



Genus VULSELLA, Lamarck. 

 [Mem. Soc. Hist. Nat. Paris, 1799, p. 82.] 



Shell subequivalve, not auriculate, longer than broad ; cardinal 

 border not furnished with teeth ; ligament similar to that in Ostrea 

 and lodged in a triangular, oblique pit ; structure of the test 

 nacreous interiorly, prismatic externally. 



Type. — Mya vulsella, Linnaeus. 



Vulsella laevigata, Tate. 



1886. Vulsella lavigata, Tate, Trans. Eoy. Soc. South Aust. vol. viii. p. 122, 

 pi. iii. figs. Za-h. 



In general form this shell resembles V. deperdita, of the Eocene 

 of Europe, from which, however, it may be distinguished in being 

 relatively narrower and in having less divergent umbones. The 

 author remarks that its resemblance to V. angustata, Deshayes, 

 of the Parisian Eocene, is very close, but that it differs by the 

 large, straight ligamental pit. 



Fimensions. — Height 26 mm. ; length 14 mm. 



Form, and Loc. — Eocene : Aldinga, South Australia. 



L. 10029. Two examples of the adult. Furchased. 



Genus PINNA, Linnaeus. 



[Syst. Nat. ed. 10, 1768, p. 707.] 



Shell equivalve, trigonal, umbones acute ; posterior side truncate ; 

 ligament linear, long, lodged in a groove ; cardinal border without 

 teeth ; nacreous, splitting into thin plates on decomposition, so 

 that fossil examples are commonly fragile, and often present the 



