603.] [Footnote 44: _Nature_, vol.xxxviii.p.

328.] [Footnote 45: A very remarkable illustration of function in an apparently useless ornament is given by Semper.

He says, "It is known that the skin of reptiles encloses the body with scales.

These scales are distinguished by very various sculpturings, highly characteristic of the different species.

Irrespective of their systematic significance they appear to be of no value in the life of the animal; indeed, they are viewed as ornamental without regard to the fact that they are microscopic and much too delicate to be visible to other animals of their own species.