The microscopic structure of the shell and ligament of cardium (cerastoderma) corbis martyn

✍ Scribed by Harold D. Mitchell

• Book ID: 102903364
• Publisher: John Wiley and Sons
• Year: 1935
• Tongue: English
• Weight: 536 KB
• Volume: 58
• Category: Article
• ISSN: 0362-2525
• DOI: 10.1002/jmor.1050580109

✦ Synopsis

Abstract

The shell of Cardium corbis is composed of three layers, an outer periostracum of conchyolin and two layers of aragonite. The outer aragonitic layer presents a laminated appearance, but in reality is made up of fibers which extend across several of the curved lamellar lines. Each fiber is enclosed in an organic sheath which can be dissolved in potassium hydroxide. The inner aragonitic layer is composed of vertical prisms which are made up of two sets of fibers inclined to each other at an angle of 55 to 60°. The outer layer of aragonite is secreted by glands on the mantle edge outside the pallial line; the inner layer is secreted by glands on the mantle area within the pallial line. The dentition is formed of the same material as the inner aragonitic layer.

The ligament is composed of two layers, the outer being less impregnated with calcium carbonate than the inner. Both layers are continuous with the organic matrix of the shell.