133 
PATELLA lata 
TAB. CCCCLXXXIV,— 1. 
Spec. Char. Obovate, depressed, nearly smooth, 
radiated ; radii about 30, distant, rounded ; 
apex very excentric. 
Not much longer than wide, very shallow, and rather 
irregular * the apex is placed at about one third the 
length of the base from the anterior edge. The radii 
are strongest and most distant upon the posterior por- 
tion. 
This is probably one of the rarest productions of the 
Stonesfield slate : it was lately in the possession of Mr. 
G. Humphries. The portion that is broken off from the 
upper part, discloses something within that has the ap- 
pearance of a section of the cup-like appendage of a Ca- 
lyptraea; but as the apex is regular and not oblique, and 
this appearance is very imperfect, it does not seem suf- 
ficient evidence of its not being a Patella : it would be 
fortunate to find a specimen showing the under surface, 
but in this the shell adheres too closely to the stone to 
allow any hopes of being able to remove it. A view of 
the muscular impression would decide it to be a Patella, 
