Bidentata has two denticles, fusiform and reddish-brown, as are all.
Much like the previous species, but no denticles and fewer whorls, and broader mouth.
Circular, flat above, mouth triangular, with a strong pinkish-white rim with three denticles.
The denticles on the spine are straight or hooked backward, in Pleuracanthus (lævissimus), the spine being flattened.
Each tooth, ...