PLATE 46, 47, 48, 49. 
triangular, between the beaks. Outline of the shell trans- 
versely oval ; its surface even, without furrows or strias, 
and frequently polished and shining. The convexity in 
each valve nearly the same. Beaks approximate; that of 
the smaller valve short and obtuse ; the other prominent, 
incurved, and more pointed. The margin deeply curved, 
giving to the larger valve a slight, and, in some specimens, 
scarcely perceptible concave wave, which is answered by a 
convex one, on the other side of the shell. 
Common in limestone. Chelmerton, Tideswell, &c. It 
varies much in size, being found considerably larger, as 
well as smaller, than the specimen we have figured. 
FIG. II, 12. 
CONCHYLIOLITHUS Anomites (rotundatus) sub- 
orbiculatus longltudinaliter sulcatus, margine sinu 
obsolete. S. p. 
A fossil shell. The original an Anomia. Perforate. Valves 
convex. Hinge straight, patulous, short. Foramen trian- 
gular. The general form of the shell somewhat orbicular, 
and in a slight degree compressed, as the convexity of the 
valves does not equal that, which is found in other Anomitas 
of the same tribe. Valves longitudinally furrowed. Mar- 
gin obtusely crenate, with a scarcely distinguishable sinus. 
The beak of the larger valve incurved. 
