The Collaborative International Dictionary of English v.0.48:

Sea clam \Sea" clam`\ (Zool.)
   Any one of the large bivalve mollusks found on the open
   seacoast, especially those of the family Mactridae, as the
   common American species. (Mactra solidissima or Spisula
   solidissima); -- called also beach clam, and surf clam.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Surf \Surf\, n. [Formerly spelled suffe, and probably the same
   word as E. sough.]
   The swell of the sea which breaks upon the shore, esp. upon a
   sloping beach.
   [1913 Webster]

   Surf bird (Zool.), a ploverlike bird of the genus
      Aphriza, allied to the turnstone.

   Surf clam (Zool.), a large clam living on the open coast,
      especially Mactra solidissima (syn. Spisula
      solidissima). See Mactra.

   Surf duck (Zool.), any one of several species of sea ducks
      of the genus Oidemia, especially Oidemia
      percpicillata; -- called also surf scoter. See the Note
      under Scoter.

   Surf fish (Zool.), any one of numerous species of
      California embiotocoid fishes. See Embiotocoid.

   Surf smelt. (Zool.) See Smelt.

   Surf whiting. (Zool.) See under Whiting.
      [1913 Webster]