81 
OSTREA canaliculata, 
TAB. C XXXV.— Fig. i. 
Spec, Char, Depressed, very long 8 , curved, two 
eared ; a descending sinus or two in the an- 
terior margin near the front; sides nearly 
parallel. 
Generally three times as long as wide ; the ears are 
rather large, nearly equal, and distinguishable in both 
valves : the posterior or concave side is often open : a 
few concentric undulations are observable near the beak 
of the lower concave valve : the upper valve is very flat, 
without a prominent beak. 
This species of oyster was sent me by Mr, Richard 
Taylor, from the Chalk Cliff at Mundsley near Cromer, 
with Magas pumilus, tab, 119, (where the locality should 
have been given as here specified,) and Terebratula 
earnea, tab, 15, fig. 5 and 6. It seems pretty well iden- 
tified by the ears both in the upper and lower valves, but 
most conspicuous on the incurved side : the convex side 
is also mostly plaited with two or more canaliculated pro- 
jections. I could discover no marks of attachment at 
the beak, which is acuminated and apparently in depen- 
dant. 
The Ostreae, so universally distributed, are very puz- 
zling in their varieties. 1 have therefore endeavoured 
to distinguish two or three here, that some reference 
may be had occasionally, if the characters I have used 
will answer the purpose of distinguishing them in the 
numerous places where they are found. 
