251 
Ccipulus vetustus (partim.), H. G-. Bronn, 1848, Index Pal., p. 217 (non Sow., sp.). 
,, trilohatlis, j. Morris, 1854, Cat. Brit. Foss., 2nd ed., p. 239. 
This is a nearly symmetrical shell, rather raised, ending in a blunt 
extremity, curved on itself hut not whorled, and keeping at some distance 
from the posterior margin of the aperture. The aperture is trilobed and 
wide open, the posterior or dorsal lobe being more pronounced than the 
others. The surface is usually covered with indistinct lines of growth. 
Dimensions. — The specimen figured by Phillips is thirty millimetres 
high, and the transverse diameter of its aperture about twenty-three milli- 
metres. The Australian specimen just described is only twenty-four milli- 
metres high, and is too badly preserved for me to figure it, or to measure 
the diameter of its aperture. 
Relations and Differences . — It is so like P. vetustmn, Sowerhy, as to 
he easily mistaken for it. I made this mistake in 1842, and other Authors 
have done the same since. The chief difference is that in P. trilohatum the 
posterior lobe is always more pronounced than in P. vetustmn, and in the 
latter the apical extremity always terminates in a small spire, which is 
entirely wanting in P. trilohatum. 
Horizon and Localities. — This is found with the preceding. 
Platyceuas altum, J. D. Dana.^ 
PI. XXIII, Fig. 5. 
Rileopsis alta, J. D. Dana, 1849, Geol. Wilkes’ U. S. Explor. Exped., p. 707, pi. 9, fig. 14. 
This species, of which I know only a small specimen, is rather straight 
and laterally compressed. Its dorsal part is arched, and its apex pointed 
and recurved forward so as to overhang the aperture when placed horizontally. 
The aperture is oval, and its antero-posterior diameter nearly double the 
transverse diameter. The surface is nearly smooth showing only rings of 
growth. 
Dimensions. — The height is five millimetres, and the transverse dia- 
meter three millimetres. 
1 [Platyce7-as {Orthonychia) altum, Dana? R. Etheridge, Junr., Records Geol. Survey N. S. Wales, 1896, 
V, p. 15, t. 1, f. 1, 2. — W.S.D.] 
2 L 
