Diagnosis. A dentition of conical, variable-sized teeth giving a sigmoidal curve when impressed into a resistant substrate. Each tooth row is at least 16-00 cm long; teeth are inferred to average 6·12 mm in diameter on one row and 7-47 mm in the other. Maxima and minima are 10-5 mm and 3.5 mm. The teeth may occur in triplets, reflecting replacement cycles.