PLATE LVIII. 
1, 2. Ostrea Macroptera. ( Long-winged Oyster.) Falciform, compressed, with large, rectan¬ 
gular wing within the curve; with irregular, deep plaits ; deeply furrowed and acutely ribbed towards 
margin of valves, producing series of deep, tooth-like processes; hinge-area wide, triangular; beaks 
long, incurved, pointed. 
3. 0. Meadii. (Mead’s Oyster.) Elongated, thick; hinge-area large ; pit wide; beaks project¬ 
ing ; attached valve deep, with longitudinal rugge; other valve plain, flat, with lateral crenulations 
near the hinge; edges irregular. 
4. 0. Undosa. (Waved Oyster.) Obliquely ovate; umbones central; sides near hinge almost 
even; on one side an indistinct, longitudinal sulcus; on the other a series of obliquely transverse, 
strong undulations. 
5. 0. Archetypa. (Original Oyster.) Umbo near one side, obtuse; with large sulcus from 
disc, and a narrower one in front; contour of shell oblique; margins undulated. 
6. 0. Undulata. (Waved Oyster.) Sub-triangular, recurved, convex; thick; beaks blunt; 
with many, longitudinal ribs and shallow sulci, with many, imbricated laminae; cicatrix elongated, 
ovate, oblique. 
7. 0. Expansa. (Expanded Oyster.) Broad; deltoidal, with obtuse angles; beaks obscure, 
hinge-area wide, flat; cicatrix broad, with sinus at beak; margin largely undulated ; surface laminar. 
8. 0. Indistincta. (Indistinct Oyster.) Oblong, obliquely triangular, surface smooth. 
9. 0. Costata. (Bibbed Oyster.) Sub-orbicular; lower valve, with many, furcated and bifurcated 
ribs; upper valve flat, with undulated margin; beak obscure. 
( 70 ) 
