The ultrastructure of the chromatophores of Crangon and Pandalus (Crustacea)

The ultrastructure of the chromatophores of two decapod crustaceans, Crangon crangon and Pandalus borealis, is investigated. The pigment appears macroscopically as small units, so-called chromatosomes. These contain separate chromatophores of different colors, and each color is composed of several chromatophores. Each chromatophore contains pigment granules, tubuli (ca. 210 Å), a network of cisternae of the endoplasmic reticulum, and mitochondria. A close contact exists between the cisternae and the pigment granules. The tubuli are arranged in thick bundles in the chromatophore extensions. The pigment granules of chromatophores of different colors are found to be structurally different. This phenomenon, as well as the structure of the whole chromatophore, is related to the vertebrate chromatophores.