164 
PECTEN complanatus. 
TAB. DLXXXYI. 
Spec. Char. Suborbicular, wider than long, orna- 
mented with thirteen broad flat elevated rays, 
concentrically striated ; one valve nearly flat, 
concave near the beak ; ears equal, square. 
Similar in size and shape to P. maximus, but distinct, 
the rays being flat, with nearly perpendicular sides ; the 
two lateral rays are blended with many striae upon the 
sides of the valve. The two valves have not, that I know 
of, been discovered in contact : we are therefore unac- 
quainted with its particular characters ; the flatter one is 
less convex than that of either P. grandis or P. maximus. 
Our intelligent friend Mrs. Murchison has obtained 
several valves of this species from the Crag at Aid- 
borough, and near Ipswich. It is also in the cabinet of 
the Rev. Mr. Leathes ; but it is by no means so common 
as the grandis. 
Besides the two species just described, there are found 
in the Crag, P. maximus and P. Jacobaeus : but I have 
only seen fragments ; and these are so identical with the 
recent species, that there is hardly any necessity for 
figuring them. 
