spirals in the coil of an elephantãs trunk, in the ãcircling {495} spiresã of a snake, in the coils of a cuttle-fishãs arm, or of a monkeyãs or a chameleonãs tail.
Among such forms as these, and the many others which we might easily add to them, it is obvious that we have to do with things which, though mathôÙeôÙmatôÙiôÙcally similar, are biologically speaking fundamentally different. And not only are they biologically remote, but they are also physically different, in regard to the nature of the forces to which they are severally due. For in the first place, the spiral coil of the elephantãs trunk or of the chameleonãs tail is, as we have said, but a transitory configuration, and is plainly the result of certain muscular forces acting upon a structure of a definite, and normally an essentially different, form. It is rather a position, or an attitude, than a form, in the sense in