Eurypterida on the one hand, and recent scorpions on the other, standing, if anything, rather nearer to the former than to the latter"; it is probable that Palaeophonus and the closely related Proscorpius still shared an adaptation to water-breathing with their nearer related ancestors and relatives.
Figure 86 Fourth leg of a recent scorpion (Buthus australis). (From Pocock)
Figure 87 Third leg of Siluric scorpion, Palaeophonus nuncius. (From Pocock)
sp, spurs and lobate sclerites; ?sp, processes possibly representing the point of attachment of spurs in Palaeophonus; cl, claws
4 This suggestion is further strongly supported by the very primitive character of the walking legs of the Siluric scorpions and the fact that they appear better adapted to a marine life than a terrestrial one, as pointed out by Pocock. In fact the legs of Palaeophonus [text fig. 87] are so much like those of the eurypterids that they at once suggest a like use, and a like habitat of the animal; hence a different one from that of the later scorpions.
5 In view of the latter suggestion, the fact of the association of the Siluric eurypterids becomes significant in indicating that these similar creatures had also a similar mode of life and the same habitat. If they were still as nearly related as Pocock asserts, it is proper to assume that the two diverging branches had not yet sought different fields of action.
6 The possibility of a creature of the shape of the Siluric scorpion finding congenial conditions in the waterlime sea is clearly brought out by Eusarcus, which bears, especially in its earlier growth stages, a striking resemblance to the scorpion [pl. 36, fig. 1] as evinced by its specific name scorpioides, and that of the British congener, E. scorpionis. We have little doubt that Eusarcus and Proscorpius were close competitors in the same field. Through these Eusarci, Pro-
