120 MITRA. 



the Pliocene of North Italy ; the latter, howeTer, is not so 

 narrow, it is minus the subangulation of the last whorl, whilst 

 the anterior half of the columella is twisted, and the plications 

 are not so prominent. It is analogous, also, with M. melaniana, 

 Lamarck, and M. digna, A. Adams, both of which are found 

 living in Australian waters. 



Dimensions. — Length 66 mm.; breadth 16 mm.; length of 

 aperture 28 mm. 



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



G. 4244. An example of the neanic stage. 



Presented hy John Bennant, ]£sq. 



G. 9360. A series illustrating stages of growth ; one specimen, 

 of the late brephic stage, having only two columellar plications. 



Purchased. 



Mitra multisulcata, sp. nov. 



[Plate V. Figs, la-d.l 



The protoconch of this species forms an interesting study ; 

 it is composed, typically, of six gradually increasing volutions, 

 polished, slightly granulated, and the anterior turns are longi- 

 tudinally striated. In the first two volutions the calcium carbonate 

 assumes a white, rather pearly colour and lustre, the succeeding 

 turns being light yellow and porcellaneous. The large number of 

 volutions indicate a long intracapsular existence. The protoconch 

 is clearly cut off from the shell proper. In some specimens ex- 

 amined there were only five volutions, and these were implanted 

 obliquely with reference to the axis of the shell. Immediately 

 the larval form escaped from the capsule it commenced to grow 

 vigorously, and at once assumed the cancellate structure so well 

 developed in succeeding whorls. 



The formation of the columellar plaits at this (brephic) stage 

 may be described as follows : — Shortly after the shell emerged 

 from the capsule the anterior portion of the columella became 

 slightly callous, and this was prolonged posteriorly into an incon- 

 spicuous ridge, which, as the animal grew, developed into a true 

 columellar plication. That portion free from callus bears, even 

 at this early stage, two small plications, which must not be 

 confounded with the bold spiral liueations, seven in number, 



