Dictionary of Ichthyology  

ctenoid scale = a scale having small spines (ctenii) on the posterior exposed portion and which hence feel rough when stroked towards the head. Typical of many Teleostei.

Sole scale from Lydekker et al. "Reptiles, Amphibia, Fishes and Lower Chordata", 1912. Photograph by Brian W. Coad.

Canadian Museum of Nature