TUEKITELLA. 237 



Dimension.i. —Length 14 mm.; breadth 4 mm.; length of 

 aperture 3 mm. 



Form, and Loc. — Eocene : Muddy Creek, Victoria. 



G. 4743. Specimen of the neanic stage of growth in which the 

 protoconch is well preserved. 



Presented hj Professor T. Rupert Jones, F.R.S. 

 G. 9423. Several examples illustrating stages of growth. 



Purchased. 



Turritella conspicabilis, Tate. 



1893. Turritella conspicabilis, Tate, Trans. Eoy. Soc. Soutli Aust. vol. xvii. 



pt. 2, p. 339, pi. Yiii. fig. 7 ; pi. is. fig. 6. 

 1895. Turritella conspicabilis, Pritchard, Proc. Eoy. Soc. Vict. vol. viii. n.s. 



p. 115. 



Typical forms of this species possess but one prominent keel, 

 whilst those of T. tristira, Tate, have three which are equal in 

 size ; and that appears to be the chief point of difference between 

 the two species. Occasionally, however, forms of T. conspicahilu 

 are found possessing two minor keels, behind the prominent 

 one, and as these develop in size the shells closely approximate 

 T. tristira as having three keels, but they are of unequal size. Its 

 author reluctantly considered T. conspicabilis as distinct. It might 

 have been advisable to regard it as synonymous with T. tristira, 

 but not having seen actual specimens of the latter, the present 

 writer hesitates to definitely make the alteration. Variation in 

 the number of spii-al keels is well exhibited by the Miocene 

 and Pliocene T. triplicata, Brocchi, of Europe, with which the 

 Australian species mentioned have considerable affinity. In the 

 Tortonian beds of Stazzano, in Piedmont, for example, one can 

 find T. triplicata with practically every variation from one 

 prominent spiral keel to thi'ee well-formed keels; and parallel 

 cases could be cited from other localities in reference to other 

 species. The number of keels is certainly not a good differentiating 

 character with Turritella. 



Dimensions. — Length 35 mm.; breadth 10-omm.; length of 

 aperture 7 mm. 



Form, and Loc. — Miocene : Gippsland, Victoria. 



G. 9430. Two examples of the adult. Purchased. 



