Note 138 — Chapter VI · CRUSTACEA (CONTINUED)—EUMALACOSTRACA (CONTINUED): EUCARIDA—EUPHAUSIACEA—COMPOUND EYES—DECAPODA

Keeble and Gamble, Phil. Trans. Ser. B., cxcvi., 1904, p. 295. In the young a constant and very simple chromatophore-system is present, but in the adult a barred, lined, or monochrome colour-pattern may be present, which is ultimately induced by the nature of the environment, and does not subsequently change. In other species of Hippolyte, and in Palaemon and Crangon, only one adult colour-pattern occurs. Thus H. varians, besides reacting to light by its chromatophores, possesses a permanent colour-pattern, which is also determined by environment.