The foregoing considerations make it not at all improbable that the tortoise on the coins of Aegina simply indicates that the old monetary unit of that island was the shell of the sea-tortoise (ἡ θαλαττία χελώνη), which was considerably larger, and therefore more valuable for making bowls, than that of the land or “mountain” tortoise (ἡ ὀρεινὴ χελώνη). There was a well-known headland on the Coast of Peloponnesus called “Tortoise Head” (Chelonates), and this creature must have been a peculiar feature of the shores of Aegina, or it would not have been chosen as the type for her coins, whether it be a religious symbol or not. At all events we know from the story of Sciron the robber, slain by Theseus, that the sea-tortoise was a familiar feature on the shores of the Saronic Gulf, as the hapless travellers who were kicked over the rocks by the caitiff were devoured by a large sea-tortoise which frequented the strand below. This creature’s picture is handed down on a well-known vase-painting which commemorates the exploits of Theseus. Finally, it may well be supposed that had not its connection with the invention of the lyre attracted to that instrument the name of “Tortoise” both in Greek and Latin, we should have found the name employed for some sort of vessel, as is the case with the Echinus. [Illustration: FIG. 45. Coin of Boeotia with shield.] Coming now to Central Greece, we find on the coins of all the Boeotian towns (with the exception of Orchomenus in her earliest issues) the well-known device of the Boeotian shield. This has been confidently pronounced to be a sacred emblem, symbolic of a common worship, conjectured to be that of Athena Itonia, whose temple near Coronea was the meeting-place of the Boeotians[404], whilst at Coronea golden shields were preserved in the Acropolis[405]. This may be so, but it is equally possible that the shield represented a common monetary unit in ancient times. The shield of early Hellas was a simple ox-hide buckler, described in Homeric language simply as an _ox-hide_[406]. Amongst barbarous peoples, as we saw above, weapons form one of the regular commodities commonly employed as currency; the Achaeans bought wine with hides as well as with oxen from the ships that came from Lemnos, and as there can be no doubt that the hide was a regular sub-multiple of the cow, it is very probable that the ox-hide shield stood in a similar relation to the cow, the chief or most universal unit; and as we find axes and half-axes among the prizes offered by Achilles as well as kettles and caldrons, so we learn from a famous passage[407] that shields were amongst the most usual articles offered as prizes and therefore were regular units of currency: “For they strove neither for an ox to be sacrificed nor yet for an ox-hide shield which are wont to be the prizes for the feet of men, but they strove for the life of the horse-taming Hector.” [Illustration: FIG. 46. Coin of Lycia.]