cuspidate: prickly pointed; ending in a sharp point; with an acuminated point ending in a bristle.
Basal breadth of all six the same (three times as large as one pore); form, three-sided prismatic, with cuspidate distal end.
Leaves much smaller, less oblique at the base, finely and regularly crenate, acuminate rather than cuspidate.
The serrations tend to be more nearly crenulate than cuspidate.
cuspidate, tipped with a sharp and rigid point; as in Fig. 140.
Polar spines three-sided prismatic, cuspidate, about as long as the axis of the shell.