148 
TEREBRATULA variabilis. 
TAB. DLXXVI. —figs. 2—5. 
Spec. Char. Orbicular or oblong, very convex, 
smooth ; the beak of the larger valve pro- 
duced, truncated, with a round perforation. 
Always very convex, but varying in shape from oblong 
oval to orbicular : the beak is large, straight, and trun- 
cated deeply ; the area within it is convex, with a large 
sinus. 
A very abundant fossil in the Crag ; but the valves 
are never found joined, and are always much worn. 
Figs. 2. and 4. are from specimens collected by our 
zealous geological friend Mrs. Murchison. 
