(class Chondrichthyes, subclass Elasmobranchii)
An order of sharks (not recognized by all authorities) that have two dorsal fins without spines and, typically, an anal fin. There are five pairs of gill slits and a spiracle is present in most species. The order includes a variety of sharks, e.g. Orectolobidae (carpet sharks), Lamnidae (mako sharks), and Scyliorhinidae (catsharks). There are about 200 species, world-wide in distribution.
Subjects: Zoology and Animal Sciences.