...nearly uniform size. These are arranged perpendicularly (or nearly so) to the surface of each lamina, so that its thickness is formed by their length, and...their extremities. A more satisfactory view of these prisms is obtained by grinding down a lamina, * It is stated by Wagner, that minute crystals of calcareous...

...columns. "The shell is thus seen to be composed of a vast number of prisms, having a tolerably uniform size, and usually presenting an approach to the hexagonal...length, and its two surfaces by their extremities." * The inner layer of such shells is remarkable for possessing in different degrees the property of...

...columns. " The shell is thus seen to be composed of a vast number of prisms, having a tolerably uniform size, and usually presenting an approach to the hexagonal...length, and its two surfaces by their extremities."* The inner layer of such shells is remarkable for possessing in different degrees the property of reflecting...

...hexagonal shape and nearly uniform size. These are arranged perpendicularly to the surface of each lamina, so that its thickness is formed by their length, and its two surfaces by their extremities. The substance forming these prisms is generally transparent, but here and there is found a dark spot,...

...nearly uniform size. These are arranged perpendicularly (or nearly so) to the surface of each lamina, so that its thickness is formed by their length, and...their extremities. A more satisfactory view of these prisms is obtained by grinding down a lamina, * It is stated by Wagner, that minute crystals of calcareous...