264 
D. largierescens, spec. nov. PI. viii., figs. 10-10a. 
Shell smooth and shining, considerably arched, six and a-half 
times as long as wide, rapidly increasing ; sculptured with dis- 
tinct, oblique, incremental lines; apical fissure a short slit or 
triangular notch on the convex side, no plug ; anterior extremity 
circular. 
Length, 44; diameter of anterior extremity, 6:5; at apex, 1; 
height of arch above the chord, 2 mills. 
This new species resembles D. subfissura, from which it differs 
by stronger curvature, by rapid increase, not so attenuated 
apically, and by the obliquely annular sculpture. The rapid 
increase in diameter and the strong curvature distinguish it also 
from recent species. 
Post-EocENE.— BEAUMARIS (SIX eXs.). 
Miocrne.—Junction-bed, Grange Burn (one ex.); Gippsland 
Lakes (one ex., J. Dennant). 
b. Apex simple, without notch or slit. 
D. laeteolum, spec. nov. 
D. lacteum, Tate, 1, p. 193, non Deshayes. 
A reference to the full description and ample illustrations of 
D. lactewm, Deshayes, in Pilsbry’s monograph of the genus, 
satisfies me that this recent species is not present in our Older 
Tertiaries. The transverse section of both is circular, but the 
rate of increase of the sectional diameter is not the same; thus 
in D. lactewm, with a total length of 30 mm., the diameter is 2°5, 
whilst in the fossil species for a length of 35 mm. the diameter is 
2:25 (vix); hence D. lacteolum is amore slender shell. It is 
straighter and more slender than the posterior part of 
D. subfissuwra, and is therefore somewht similar to D. acriculum, 
from both distinguished, of course, by the absence of an apical 
notch. 
Tenison-Woods recorded D. lactewm (?) as a Table Cape fossil, 
but the only Leevidentalium at that locality, so far as known 
from my own and other collections, is D. pictile, which I am dis- 
posed to regard as the shell observed by him. 
Kocrens.—Muppy CREEK and Gelibrand River, Victoria. 
Section Fusriaria, Stoliczka, 1868. 
Shell smooth, or with annnlar sculpture ; slit long. 
D. aericulum, Zate, 1, p. 192; id., Harris, 2, p. 296. 
Shel! curved, slender, smooth. 
EocENE.—Muppy CreEEK, Victoria. 
D. australe, Sharp and Pilsbry, 3, p. 192. . 
Entalis annulatum, Tate, 1, p. 191. Name preoccupied by 
Gmelin, by Sandberger, and by Meyer. 
