The appendages of the second pair are large and prehensile, as in scorpions, but are armed with spines, to impale and hold prey.
Rough Castle, near Falkirk, is very much smaller; it is remarkable for the astonishing strength of its turf-built and earthen ramparts and ravelins, and for a remarkable series of defensive pits, reminiscent of Caesar's lilia at Alesia, plainly intended to break an enemy's charge, and either provided with stakes to impale the assailant or covered over with hurdles or the like to deceive him.
In heraldry a "pale" is a band placed vertically in the centre of a shield, hence "in pale" or "to impale" is used of the marshalling of two coats side by side on a shield divided vertically.