TEIVIA. 213 



their thin outside covering ; anterior channel not prolongecl, wide 

 and slightly reverted. 



Dr. Gray' selected the following as the type of the genus : — 



Type. — Cyprcea europaa, Montagu. 



Trivia avellanoides, M'Coy. 



1867. Ctjpraa [Trivia) avellanoides, M'Coy, Ann. Mag. Nat. Hist. 3rd ser. 

 vol. XX. p. 436. 



1876. Cijprtea {Trivia) avellanoides, M'Coy, Prod. Pal. Vict. dec. iii. p. 36, 



pis. xxviii., xxix., figs. 3-3tf. 



1877. Trivia europcea, Tenison- Woods, Pap. Eoy. Soc. Tas. 1876, p. 109. 



1878. Trivia avellanoides, R. Etheridge, jun., Cat. Aust. Foss. p. 168. 



1879. Trivia minima, Tenison- Woods, Proc. Linn. Soc. N.S.W. vol. iv. 



p. 4, pi. i. fig. 8. 

 1890. Trivia avellanoides, Tate, Trans. Roy. Soc. South Aust. vol. xiii. pt. 2, 



p. 213. 

 1893. Trivia avellanoides, Tate and Dennant, id. vol. xvii. pt. 1, p. 222, 



1895. Trivia avellanoides, Tate and Dennant, id. vol. xix. pt. 1, p. 111. 



1896. Trivia avellanoides, Pritchard, Proc. Roy. Soc. Vict. vol. viii. n.s. 



p. 146. 



Distinguished by its immense size (for the genus), it is more 

 globose, and has more distant ridges than has T. australis ; the 

 young closely resemble T. europcea, from which they can only be 

 separated with difficulty, the principal differentiating characters 

 being a more pronounced dorsal furrow, a prominently thickened 

 lip, and obscurely traceable spire-whorls. Professor Tate states 

 that dwarfed examples differ from T. europma by much the same 

 characters as the species does from T. australis, but that is hardly 

 borne out on comparison with a number of specimens of the 

 European species referred to. T. minima. Professor Tate says, is 

 an early stage of growth of T. avellanoides. 



Dimensions. — Length 29 mm. ; breadth 23 mm. 



Furm. and Loc. — Eocene : Victoria. 



73222. Series illustrating stages of growth ; from Brighton. 



Purchased. 



G. 4307. Examples of the neanic and gerontic stages ; from 



Muddy Creek. Presented hy John Dennant, Esq. 



G. 9415. Four specimens ; from Muddy Creek. Purchased. 



> Proc. Zool. Soc. 1847, p. 142, genus No. 104. 



