374 Proceedings of the Royal Physical Society. 



genus in the older rocks, therefore gives strong support to 

 the doctrine of "descent with modification." As to the 

 importance of the find, it may be as well to quote Professor 

 Laurie's own words, viz. : " Looking at the fauna of this 

 bed as a whole, it may safely be said to have yielded more 

 information of importance and interest concerning these 

 fossil Arthropoda than any other single deposit." ^ 



AEACHNIDA, 



The first record of a Scottish Palseozoic Scorpion is by 

 Dr Henry Woodward in a paper before the Geological 

 Society in 1873, when he describes a doubtful tail segment 

 of Eoscorpius from the Lower Carboniferous rocks of Carluke. 

 In 1882 a paper was read by me before the Eoyal Society of 

 Edinburgh, in which three new species of Eoscorpius were 

 described from the Geological Survey collections made by 

 Mr A. Macconochie from tht Lower Carboniferous rocks at 

 the famous locality of Glencartholm, near Langholm, and by 

 the late Mr James Bennie in the Coal-Measures of Fife.^ Up 

 to that time these were the oldest known Arachnida; but in 

 1884 Lindstrom announced the discovery of a Fossil Scorpion 

 from the Upper Silurian (Ludlow) rocks of Gothland, which 

 was afterwards described by Thorell and him under the 

 name of Palceophonus nuncius? It was truly a messenger, 

 for immediately on the announcement of its discovery the 

 late Dr Hunter-Selkirk produced a species of Palceophonus 

 which was found in the Upper Silurian (Ludlow) rocks of 

 the Logan Water, near Lesmahagow, in 1883, which he 

 named P. caledonicus} This was soon followed by the 

 announcement of an American Silurian Scorpion, Proscorpius 

 Oshorni, by E. P. Whitfield, from near the top of the Upper 

 Silurian rocks.^ The chief characteristics of all these Silurian 

 Scorpions is the large size and forward position of the ocelli, 



1 Me7n. Geol. Sur,, " The Sil. Rocks of Britain," p. 595, 1899. 



2 Trans. Roy. Soc. Edin., vol. xxx. pp. 397-412, 1883. 



3 T. Thorell and G. Lindstrom, "On a Silurian Scorpion from Gothland," 

 Kon. Svenska. Vetensk. Akad. Handl., Bd. xxi. No. 9, 1885. 



4 Nature, vol. xxxi. p. 295, 1884. 



5 Science, vol. vi. p. 87, 1885. 



