143 



authors) in having a longer spire and canal, whilst the columellar 

 plaits are more central. The presence of an umbilicus in Latirus 

 has also been regarded as a differentiating character, but it is not 

 constant. On the other hand, Peristernia is credited with having 

 a recurved canal, in which particular many of the Australian 

 fossils here called Latirus agree with it, though their canals are 

 long. It is questionable whether the slight and inconstant 

 differences indicated warrant generic separation, the distinction 

 between Latirus and Peristernia being entirely arbitrary. How- 

 ever that may be, the Australian forms alluded to are, in the 

 ensemble of their characters, more nearly related to the former than 

 to the latter. 



Ti/pe. — Latirus aurantiacus, Montfort. 



Latirus approximans, Tate (sp.). 



1888. Peristernia approximans, Tate, Trans. Eoy. Soc. South Aust. vol. x. 

 p. 153, pi. ix. fig. 2. 



Shell fusiform ; spire elevated ; whorls medially subangulate, 

 spirally lineate, longitudinal costae broad, distant, subacute at 

 the peripheral subangulation ; body-whorl sloped and constricted 

 anteriorly, the costae becoming obsolete on the front half, though 

 corrugated lines of growth persist, and the spiral lineations are 

 very conspicuous ; aperture ovate, deeply channelled in front ; 

 outer margin curved, lirate within ; inner margin enamelled, the 

 enamel continuing from the suture, in the neighbourhood of which 

 is a small denticle ; columella excavated, umbilicate, having a 

 small oblique fold opposite the entrance to the canal ; the latter 

 is long, broad, curved, and slightly turned up at its extremity. 



The columellar fold can hardly be termed a plication, and is not 

 so well pronounced as in the majority of characteristic species of 

 Latirus. Professor Tate discusses its affinities at some length. 



Dimensions. — Length 27 mm.; breadth 14 mm.; length of 

 aperture 9-5 mm. ; length of canal 8 mm. 



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



G. 9459. An example of the adult, and two specimens 

 illustrating the neanic stage. Purchased. 



