444 Proceedings of the Roijal Physical Society. 



Eurypterids differ so much in the construction of their limbs 

 from the E. remipes of Dekay, the type of the genus, that 

 they would require to be placed in a new one, for which I 

 proposed the name Glyptoscorpius} As the above-described 

 carapace differs from any hitherto figured or described, I pro- 

 pose to call it GlyptoscoTjpiiis Kidstoni, after the distinguished 

 botanist, Mr Eobert Kidston. 



The squamiform ornamentation has hitherto been con- 

 sidered as characteristic of the Eurypterids. It would there- 

 fore be of interest to see whether it was confined to them. 

 It has already been shown above that it is not so, for it 

 occurs on the tests of their near congeners, the trilobites, 

 the peculiarly Silurian family of the Asaphidpe. Salter says of 

 Asaphus tyrannus^ "The sculptured lines, which are veri- 

 table plicae or folds of the crust, are wavy aud interrupted, 

 following a general curve all round the margin, but sinuous 

 and inosculating with each other." Again, speaking of 

 Illcenus Barriensis,^ " The whole head is covered with the 

 peculiar squamous lineation characteristic of the Asaphida^. 

 Among recent or fossil Crustacea (the trilobites, owing to 

 their arachnid affinities, being excepted) such markings may 

 be looked for in vain, but a similar sculpturing is to be 

 found on the limbs of the recent arachnids, the phalangids or 

 harvest-men." 



It has been already stated that small fragments of Euryp- 

 terid test may be obtained in great quantity from the 

 carboniferous rocks of Scotland, and a large number of such 

 fragments has accumulated in the Geological Survey collec- 

 tion, and these exhibit a great variety in the pattern and 

 size of the ornament. The study of the ornamentation on 

 the present carapace has been of great value, as it shows that 

 even upon such a small area as it exhibits, a great variety 

 of ornamentation may obtain. It would therefore be rash in 

 the extreme to venture on the identification of species by 

 means of these markings upon fragments where the exact 



1 Trans. Roy. Soc, Edinb., vol. xxx., part ii., p. 516, 



2 Monograph, British Tiilobites— Salter, Palceontographical Soc, 1864-1883, 

 p. 151. 



'^ Ibid., V. 206. 



