bonnet shark

from WordNet (r) 3.0 (2006)

bonnet shark
    n 1: small harmless hammerhead having a spade-shaped head;
         abundant in bays and estuaries [syn: {shovelhead},
         {bonnethead}, {bonnet shark}, {Sphyrna tiburo}]

from The Collaborative International Dictionary of English v.0.48

Shovelhead \Shov"el*head`\, n. (Zool.)
   A shark ({Sphryna tiburio}) allied to the hammerhead, and
   native of the warmer parts of the Atlantic and Pacific
   oceans; -- called also {bonnet shark}.
   [1913 Webster]