cow sharks

from The Collaborative International Dictionary of English v.0.48

Notidanian \No`ti*da"ni*an\, n. [Gr. ? back + ? comely.] (Zool.)
   Any one of several species of sharks of the family
   {Notidanidae}, or {Hexanchidae}. Called also {cow sharks}.
   See {Shark}.
   [1913 Webster]