CENSUS OF THE OLDER TERTIARY FAUNA OF AUSTRALIA, 383 
Cossmann,' states that my Epidromus citharellus “est absolu- 
ment identique au Plesiotriton velutella”; this opinion is based 
on my figure and description, and not by actual comparison. 
E. citharellus is, however, correctly placed, it being without 
columella plaits. 
I believe it is generally admitted by my co-workers that, what- 
ever ages may be assigned to the main mass of the Older Tertiary, 
the basal beds of the Aldinga section are Eocene, and the occur- 
rence of Plesiotriton in the Aldinga and Cape Otway deposits is 
one of many evidences of their approximate contemporaneity. 
PLESIOTRITON DENNANTI, spec. nov. (Plate 19, fig. 1.) 
Shell elongate conic; pullus relatively small, papillary, of one 
and a-half smooth turns. Spire-whorls five, moderately convex, 
closely tessellated by flattish spiral and axial riblets, a little 
nodulose at the intersections of the primary riblets, slender axial 
threads crowd the whole surface. The earlier spire-whorls have 
about seven to ten spiral riblets, and with the revolution of the 
spire an intermediate riblet appears between them. There are 
from one to two varices on each whorl. Aperture elongate-oval, 
rounded behind, narrowed at the front and extended into a short 
slightly recurved and upturned canal; outer lip varicially thickened 
externally, crenately dentate on the inner margin; a thin callus 
covers the parietal wall; columella with two stout spiral plaits, 
situated in about the posterior one-third. Length 28, breadth 12, 
length of aperture 17. 
Eocene, Cape Otway, Victoria. The species name is in com- 
Preah to _ RIE who brought it to my notice as a species 
of Plesio 
This new species differs from P. varicosus by more elongate 
Shape and in the details of ornamentation. In the original deserip- 
tion of Cantharus varicosus, no reference is made to the columellar 
Plications which were concealed by matrix ; subsequent develop- 
ment has revealed two stout plaits. 
—____ 
1 Ann. Geol. Univ., Vol. v., p. 1089, 1889. 
