42 DTTBLIN TTNIYERSITY 



other species, Chiton siculus, Gray, and C. fascicular is, Linn., in the 

 Tertiary strata of Sicily. 



After these discoveries Mr. Salter, in 1846, added another much 

 more remarkable example, that of a species of Chiton from the lower 

 beds of the Silurian strata at Coolin, Cong, in the county of Galway. 

 This he named Helminthochiton Griffithii, proposing a new generic term 

 to include the elongated fossil forms. 



In 1848 Mr. Searles Wood described and figured in his magnificent 

 Monograph on the Mollusca from the Crag of England, three species of 

 fossil Chiton, one of them, C. strigillatus, being new, C. fascicularis, 

 Linn., and C. Hissoi, Payr, identical with species living in our seas at 

 the present day. 



About the same time M. Eudes Deslongchamps discovered in the 

 Great Oolite or Bathonian of Langrune, the posterior or anal plate of a 

 species of Chiton, which he named Chiton KonincMi, this being the first 

 discovery of the genus in secondary strata. 



In 1852 M. Terquem added a new link to the chain uniting the Pa- 

 laeozoic Chitons to those of the present epoch, by the discovery of 

 C. Deshayesii, a new species from the middle Lias of Thionville. 



After this Mr. F. A. Eoemer described and figured, in 1855, a new 

 species of Chiton obtained from the upper part of the Devonian strata 

 near Grund, which he named C Jcevigatus ; and figured another species 

 without naming it ; this Professor De Koninck has proposed to designate 

 as Chiton tumidus. 



In 1 856 another species was obtained from Permian strata at Tun- 

 • stall and Humbleton Hill, which was described, in 1857, by Mr. J. W. 

 Kirkby, under the name of Chiton Howseanus. 



Professor De Koninck, in 1857, described, by the names of Chiton 

 Gray anus and C. Wrightianus, two new species, of great interest, from the 

 Upper Silurian formation nearly Dudley, — these remarkable examples, 

 by their occurrence, in the Wenlock limestone, furnishing another link 

 to the chain : thus leading on from the Lower to the Upper Palaeozoic 

 epoch.* 



In March, 1859, Mr. J. "W. Kirkby described, in the " Proceedings 

 of the Geological Society of London,' ' four additional Permian species 



* Professor De Koninck's description of these British species, with the accompanying 

 illustration, Plate II., will be found at the conclusion of this article. 



