Taxonomy of Finfish (1+2)

TRIAKIDAE : Houndsharks

    5 gill slits, the last pair posterior to pectoralfin origins;
    Teeth either numerous, small, cuspless (or weak-cusped) arranged in a pavement (Mustelus)
    First dorsal fin its base entirely anterior top elvic fins: second dorsal fin somewhat smaller than the first, originating ahead of anal fin; anal fin as large as or smaller than the second dorsal;
    Caudal fin without keels or precaudal pits.
    Intestine with a corkscrew or auger-like spiral valve,