Proscylliidae (Paperback)

High Quality Content by WIKIPEDIA articles! The finback catsharks are a small family (Proscylliidae) of sharks, with only 7 species in 4 genera. The ground sharks, order Carcharhiniformes, are the largest order of sharks; they are also called whaler sharks. With over 270 species, carcharhiniforms include a number of common types, such as the blue shark, catsharks, swellsharks, and sandbar shark. Members of the orders are characterized by the presence of a nictitating membrane over the eye, two dorsal fins, an anal fin, and five gill slits.