174 



the fronts of the expansions are granose. Half-way between 

 the varices an obscure longitudinal rib occurs, rising into a small 

 tubercle at the point of intersection with the prominent spiral 

 ridge at the periphery. The aperture is elongately ovate, is lined 

 with a thin plate of enamel, which is somewhat detached from the 

 columella in adult specimens, and is slightly grooved posteriorly ; 

 outer margin crenulate, denticulate within ; canal long, almost 

 closed. 



Except that the wing-like expansions are more fully developed, 

 and the aperture is not spread out, it is like M. tripteroides, 

 Lamarck, of the Eocene of the Paris Basin. 



Dimensions. — Length 28 mm.; breadth 18 mm.; length of 

 aperture 6 mm.; length of canal 12 mm. 



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



G. 4292. An example of the adult. 



Presented ly John Bennant, Esq. 



G. 9448. A series illustrating stages of growth. Purchased. 



Murex (Triplex) calvus, Tate. 



1888. Murex [Pleronotus) calvus, Tate, Trans. Eoy. Soc. South Aust. vol. x. 

 p. 6, pi. i. fig. 11. 



1895. Murex (Pteronotus) calvus, Tate and Dennant, id. vol. xix. pt. 1, 



p. 111. 



1896. Murex [Pteronotus) calvus, Pritchard, Proc. Eoy. Soc. Vict. vol. viii. 



N.s. p. 79. 



This species is closely allied to M. velificus, from which it differs 

 in not having the foliated varices so greatly expanded, a relatively 

 shorter spire, the intervariceal nodulations, or short, tuberculate, 

 longitudinal ribs, are much more prominent, whilst the plate lining 

 the aperture is spread out all round, and is more deeply sinuated 

 posteriorly. 



It has considerable analogy, as Professor Tate remarks, with 

 the living M. rubridentatus, Reeve, in regard to shape and obliquity 

 of varices, but has only one intervariceal longitudinal short rib. 

 It differs primarily from the modern M. pmnatus, Wood, in not 

 having the aliform expansions interrupted, and its spire is shorter. 

 It is more closely allied to the Paris Basin M. trifteroides, Lamarck, 

 of which, indeed, it may only be a local variation. In the 



