Stropheodonta galatea (Billings) 



Page i88 



15, 1 6 Opposite sides of a silicified specimen showing the character of the 

 plications and the hinge, x 2 



17 A portion of the hinge enlarged to show the denticulations. x 3 



18 Enlargement of the surface striae from the same specimen, x 5 

 19-21 Interior of the brachial valves showing cardinal process, muscle 



scars and denticulate hinge. (19, 21 x 2) 



22 A silica replacement showing the cast of the interior of the ventral valve 



23 A ventral valve with very regular and undivided plications, x 2 



24 Dorsal view of a specimen, x 2 



25, 26 Ventral valves showing differences due to fasciculation of the ribs 

 and development of the radial striae, x 2 

 Grande Greve limestone ; division 2. Grande Gr^ve 



323 



