40 
ferior Oolite and their different locality would have con- 
firmed us in the idea, did not that species also occur in 
the blue Olay Cliff beyond the Old Castle near Wey- 
mouth ; they are also both found together in the opposite 
Kingdom at a place called Vaches noires near Honfleur. 
Fig. 3. represents a small specimen from France, and 
in Mr. G. B. Sowerby’s work upon Genera is a figure of 
the T. costa ta from near Weymouth, taken from one 
of Miss Benett’s specimens. 
There is an unfortunate circumstance attending the 
Generic name Trigonia ; it has long been applied to a 
genus of Plants, and still remains in Wildenow’s Spec. 
Plantarum, a circumstance that has been hitherto over- 
looked, and the name has become so familiar to Con- 
chologists that we are unwilling to change it; otherwise 
we should recommend Lyridon as a substitute from the 
resemblance of the lines upon the teeth about the hinge 
to the strings of a harp. 
i 
