Page:American Seashells (1954).djvu/547

Rh 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 toA'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.