MACTRIDAE 449 



Genus Miilinia Gray 1837 

 Miilinia lateralis Say Dwarf Surf Clam 



Plate 32-0 



Maine to north Florida and to Texas. 



% to V2 inch in length, resembling a young Spisula or Mactra, moder- 

 ately obese, beaks quite prominent and near the center of the shell and point- 

 ing to\A'ard each other. Exterior whitish to cream and smoothish, except for 

 a fairly distinct, radial ridge near the posterior end. Concentric lines plainly 

 seen in the thin, yellowish periostracum. Distinguished from young Spisula 

 solidissima which have a proportionately much larger chondrophore in the 

 hinge and which have tiny, saw-tooth denticles on the lower anterior and 

 lateral hinge-teeth. A very abundant species in warm, shallow water in sand. 



Genus Labiosa iMoller 1832 



Posterior slightly gaping. Shell fragile. Hinge with a prominent chon- 

 drophore. Cardinal teeth small and close to the chondrophore. Ligament 

 submerged, except at the anterior end, and separated from the chondrophore 

 by a shelly plate. Raeta Gray 1853 is the same. This is also Anatina Schu- 

 macher 181 7, not Bosc 18 16. 



Labiosa plicatella Lamarck Channeled Duck Clam 



Plate 32q 



North Carolina to Florida, Texas and the West Indies. 



2 to 3 inches in length, Y:, as high, egg-shell thin, but moderately strong. 

 Concentric sculpture of smoothish, distinct ribs which on the inside of the 

 valves show as grooves. Radial sculpture of very fine, crinkly threads. Color 

 pure white. Formerly known as Raeta canaliciilata Say. R. cainpechejisis 

 Gray is also a synonym. Commonly washed ashore, especially along the 

 strands of the Carolinas, but rarely seen alive. 



Labiosa lineata Say Smooth Duck Clam 



North Carolina to the north % of Florida and to Texas. 



2 to 3 inches in length, % as high, fairly thin but strong. White to tan 

 in color. Moderately smooth, except for irregular growth lines and tiny, but 

 distinct, concentric ribs near the beaks. Posterior end with a distinct radial 

 rib behind which the shell gapes with flaring edges. Uncommon in most 

 areas of its range. 



