Tertiary. | PALZONTOLOGY OF VICTORIA. [Mollusea. 
Prate XLIV., Fras. 2, 3. 
CARDIUM (PROTOCARDIUM) ANTI-SEMIGRANULATUM 
(McCoy). 
Description. — Rotundato-quadrate, gibbous; respiratory angle (between 
posterior and ventral margin) obtusely rounded, posterior margin nearly straight, 
ventral margin slightly convex, anterior margin rounded. Posterior slope with very 
fine simple ridges (about sixteen in 2 lines at 1 inch from beak), closely set 
with small arched tubulo-conical spinose tubercles; rest of surface nearly smooth, or 
with very faint Jongitudinal strize (about eighteen in 2 lines at 1 inch from 
beak); about sixteen crenulations of the inner edge of ventral margin, and about 
eight on edge of posterior slope in a space of 2 lines at 13 inches from beak. 
Length from anterior to posterior margin, 1 inch 10 lines; depth of one valve, +435; 
from beak to opposite ventral margin, 5, 
This is one of the extraordinarily close representatives of well- 
known European Tertiary fossils found in our strata of similar age. 
It is closely related to Cardium (Protocardium) semigranulatum 
(Sow.) of the Bracklesham Bay, Barton, Colwell Bay, Upper 
Eocene or Oligocene strata of the Hampshire coast and Isle of 
Wight, and besides a less and more evenly convex ventral margin, 
I can only distinguish it with certainty on careful comparison of 
specimens from the English localities, by the greater fineness (or 
larger number in a given space) of the longitudinal strie of the 
body of the shell and the spinulose ribs on the posterior slope, and 
of the corresponding crenulations of the margin. In this respect 
the French Eocene nearly allied species, C. semistriatum, C. 
semiasperum, C. parile, C. fraudator, and C. Wateleti of Deshayes 
are still farther removed from our species. The spinulose ridges 
on the English specimens of C. semigranulatum, from the Brackle- 
sham Bay strata, are only about nine in the space of two lines at 
one inch from the beak, while our representative form has sixteen 
in a corresponding space. 
Rare in Lower Miocene Tertiary of Moorabool. 
EXPLANATION OF FIGURES. 
Plate XLIV.—Fig. 2, average specimen, natural size, imperfect near the beak. Fig. 2a, 
profile view of same specimen, Fig. 2b, curved tubular spines on posterior ridges magnified. 
Fig. 2c, portion of surface of posterior slope and middle of the shell magnified to show the 
spinulose character of the former and the faint indication of striae seen on the latter with the 
lens. Fig. 3, rostral view of another specimen, natural size, 
Freperick McCoy. 
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