THE EURYPTERIDA OF NEW YORK 397 
Whitfield inclined tc the view that the creature was aquatic mainly 
because he failed to find the stigmata on the supposed ventral plates. 
Thorell and Lindstr6ém considered Palaeophonus nuncius, in 
which they observed a possible stigma on the ventral plate, as an un- 
doubted air breather and have acclaimed this as the most important proof 
of a Siluric terra firma, with an air-breathing fauna. Laurie, in describ- 
ing 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 necessarily so delicate in texture that we know 
very little of their structure arid 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 integu- 
ment, the part of the plate exposed belonging, according to his interpre- 
tation, 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,' 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 
1 Against this again it is asserted by Fritsch [1 go4, p. 64] that the specimen exposes 
the dorsal side and that only some of the ventral organs are pressed through the muti- 
lated carapace and that it hence could not show stigmata. 
