Palceontology of Older Tertiary of Victoria. 107 



tively slender spire of the latter species, though the characters 

 of the outer lip are more closely allied, but even here there are 

 distinct differences. 



Voluta hamiltonensis, sp. nov. PI. YIIL, Fig. 5. 



Shell fusiform, with its spire less than half the length of the 

 shell, capped by a remarkably large smooth mammillate embryo. 



Embryo varies in size from about fourteen to ten millimetres 

 in diameter, and from eleven to ten millimetres in height, and 

 has a much swollen appearance, consisting of two obliquely 

 enrolled whorls, their axis of enrolment making an angle of 

 from forty to fifty degrees with the axis of the shell. 



Embryonic whorls Succeeded by four very slightly convex 

 whorls with an impressed suture, and bearing faint spiral striae, 

 a few of the striae tending to become stronger and more thread- 

 like on the anterior slope of the whorls. The spiral ornament is 

 crossed transversely by very fine regular lines of growth, which 

 on the earlier spire whorls are somewhat sigmoid, but soon 

 become backwardly arched to a less degree ; in some specimens 

 the lines of grovvth become so strong and raised as to give rise to 

 narrow line. Body whorl somewhat flattened medially on the 

 back. Young shells of this species are much more strongly 

 spirally striate on the rather abrupt anterior slope towards the 

 notch. 



Aperture lanceolate : outer lip barely ascending the penul- 

 timate whorl where it joins the much thickened and conspicuous 

 enamel pad of the inner lip ; outer lip thickened, reaching its 

 maximum in this respect about two-thirds the distance from the 

 suture, and being almost margined within, while without, the 

 margin is distinct. Columella bearing in the young shells three 

 plaits, but adults show some variation by the presence of two 

 additional smaller plaits, one between the anterior and the next 

 above it, and the other forming part of the strong callosity above 

 the posterior one. The colour marking preserved shows that 

 this species bore narrow zig-zag lines of a reddish or brownish 

 colour, parallel to one another, and about five or six millimetres 

 apart. 



