Whitfield inclined to the view that the creature was aquatic mainly because he failed to find the stigmata on the supposed ventral plates. Thorell and Lindström considered Palaeophonus nuncius, in which they observed a possible stigma on the ventral plate, as an undoubted air breather and have acclaimed this as the most important proof of a Siluric terra firma, with an air-breathing fauna. Laurie, in describing Palaeophonus loudonensis says [1899, p. 576] it does not necessarily follow that this scorpion was an air breather, since "the characters which mark it as a scorpion may well have been developed before the terrestrial mode of life and consequent modification of the respiratory organs took place." He adds that "unfortunately these respiratory organs are necessarify so delicate in texture that we know very little of their structure and arrangement in any of the fossil Arthropoda"; and Pocock [1901, p. 305] shortly after Laurie, argued that the Swedish P. nuncius lacked the stigmata, considering the stigma or spiraculum described by Thorell as a fortuitous crack in the integument, the part of the plate exposed belonging, according to his interpretation, not to the third mesosomatic somite, but to the second, which bears no stigmata in the scorpions. Pocock goes further and claims that the last two plates of the mesosoma of P. nuncius, considered by Thorell as tergites, are sternites and fail to show the stigmata which constituted Thorell's reasons for considering them as tergites. Pocock also failed to find the stigmata in P. hunteri, which Peach thought to have seen, and, believing that this Scottish specimen exposes the ventral side,[1] he assumes a sceptical attitude to the presence of stigmata in the Siluric scorpions. The idea that the Siluric scorpions lived on land, he says, is "less easy to reconcile with the facts that both the known specimens are relatively in an admirable state of preservation, and were met with in strata of undoubted marine origin, containing abundance of admittedly marine
- ↑ Against this again it is asserted by Fritsch [1904, p. 64] that the specimen exposes the dorsal side and that only some of the ventral organs are pressed through the mutilated carapace and that it hence could not show stigmata.
