1) The number of ribs differs according to various localities and horizons. In the recent specimens it is necessary to examine the relation between the number of ribs and the environments. 2) The growth relation between the height and the length in the fossil specimens of Anadara granosa (LINNE) can be expressed by the equation H=aL^b, where H is the height, L the length. 3) The local constant Am may be useful in palaeontology and stratigraphy. 4) The convexity of the shells is more prominent in the younger individuals. In Anadara granosa (LINNE), the change of the convexity of shell according to growth is similar in both valves.

View full abstract