249 
Belations and Differences. — This beautiful species resembles the pre- 
ceding by the form of its folds and the distance between them ; it differs by 
the shape of its cross section, the long sides of which arc relatively longer 
than those of (7. hevigata ; it differs most decidedly by the double canal and 
its angles, and by the obliquity of its transverse folds. This last miglit be 
accidental. 
Horizon and Localities . — According to Dana this species is found at 
Glendon. The only specimen sent me was found by the llev. W. B, Clarke 
in a grey micaceous sandstone about one and a half miles from Maitland. 
C/rtss— GASTEROPODA, 
Ord6>r~PROSOBIlANCHIATA. 
DENTALIUM, Linneeus. 
Dentalium coenu, L. G. de Konincli. 
PI. XXIII, Fig. 4. 
This is a small recurved shell, ending in a sharp point at its lower 
extremity ; its surface is smooth, and its test relatively thick. The only 
specimen I have seen is deformed by pressure, so that I cannot give the 
exact shape of its transverse section. By uplifting a small piece of the test 
towards its lower extremity I saw that it was grooved, not chambered, there- 
fore I could refer it to its genus. 
Dimensions . — This specimen was only fifteen millimetres long, but 
probably the species caii reach a much greater size. Its greatest transverse 
diameter Avas three millimetres. 
Delations and Differences . — McCoy has described a small Carbon- 
iferous species, D. inornatum, but it is very unlike this one, being much less 
conical and much thinner, so that it cannot be confounded with this. 
Horizon and Localities. — D. cornu was found in a grey argillaceous 
limestone near Kama. 
