265 
Shell large, nearly straight, with annular lines. 
Eocene.—Muppy Creek and Shelford, Vict. 
Post-Eocenr.—Spring Creek, Vict. 
A variant of this species occurs at Spring Creek, which is 
usually more slender, the length to the breadth being 12 to 1, 
as against 10 to 1; and in one individual the apical slit is 18 
millimetres. 
Section EpisipHon, Pelsbry and Sharp, 1899. 
Apex entire with a projecting tube. 
a. Shell iongitudinally ribbed. 
D. aratum, Tate, 1, p. 192; id., Harris, 2, p. 293. 
This species has a truncated apex of about one millimetre 
diameter from the orifice of which protrudes a very short, smooth 
subpellucid tube. The truncated end is of a white ceramic 
lustre and is concentrically striate; the whole appearances 
suggest that the embryonic and attenuated tip has been cast off. 
D. aratum differs from all congeners in the group by its 
longitudinal ornament and sculpture. 
Eocene.—RIverR Murray Cuirrs and Muloowurtie, S. Aust.; 
Bellarine Pen. (Hall and Pritchard), Muddy Creek, Gelibrand 
River, Fyansford, Birregurra, Mornington, Camperdown, Cape 
Otway (Victoria). 
Post-Eocrene.—Spring Creek. 
b. Shell with annular ridges. 
D. tornatissimum, spec. nov. PI. viii., figs. 7-7a. 
Shell very small, nearly straight; sculptured with annular 
rounded ridges, more or less regular throughout the whole length 
(here and there a stouter annulation of about double breadth), 
wider than the deep narrow intervening grooves, ten in a 
millimetre length of the apical part. 
Test very thick. Apex simple, circular, truncate ; projecting 
from the aperture is a round pipe about ‘16 in diameter and -2 
mm. long. Anterior extremity not known; all the specimens 
present the appearance of being fragments of larger individuals ; 
however, the transverse section is circular. 
Length 7, diameter at aperture -9, at apex ‘55 mill. 
Mi0cENE.—GIpPPsLaND Lakes (4 exs., J. Dennant). 
This species is closely related to D. tornatum, Watson, dredged 
off Levuka in 12 fms. (Challenger Exped.), which is distinguished 
from other components of Pilsbry and Sharp’s subgenus 
Episiphon by its annular grooves. D. tornatum is described as 
possessing deep, close-set, slightly oblique, annular grooves in the 
upper part of the shell only, becoming shallower further down 
and cease at last rather abruptly. The fossil analogue has the 
Ss 
