Find the word definition

Wikipedia
Huaiheceras

Huaiheceras is an ellesmerocerd genus from China, and type for the Heuhiceratidae that lived during the Late Cambrian. The shell is small, tubular, gently expanding and with a slight curvature. The siphuncle, which is proportionally naarrow, is on the outer, concave curvature of the shell, suggesting it is exogastric. Septa are close spaced.

The genus Huaihecerina is similar but has a slightly greater curvature and greater rate of expansion.