rom the Upper Silurian ‘ Wenlock Limestone’ of Dudley. 93 
Before the publication of the work of M. de Ryckholt, Mr. 
King had already announced the occurrence of a Chiton found by 
Mr. Loftus in the Permian formation near Sunderland*, and 
described later under the name of C. Loftusianus+,—on this side, 
M. Philippi having made known two other species (C. siculus, 
Gray, and C. fascicularis, Linn.) from the tertiary strata of 
Sicily t. 
Attes these discoveries, Mr. Salter in 1846 added another and 
much more remarkable example, that of a species of Chiton from 
the lower beds of the Silurian strata of Ireland. That author 
proposed on the occasion a new genus, under the name of Helmin- 
thochiton, for the purpose of receiving the palzozoic species§ ; 
but as it is not distinguished by any essential character from 
the ordinary genus Chiton, it can merely serve to denote a section 
of that genus. 
In 1848 Mr. Searles Wood described and figured, in his mag- 
nificent Monograph on the Mollusca from the Crag of England, 
three fossil species of Chiton, one of them being new (C. strigil- 
latus), and the two others identical with species livmg in our 
seas at the present day (viz. C. fascicularis, Linn., and C. Rissoi, 
Payr.||). 
About the same date M. Eudes Deslongchamps, to whom 
science is indebted for a great number of excellent works on 
the Jurassic fossils of the environs of Caen, discovered in the 
Bathonian beds of Langrune the posterior or anal plate of a 
species of Chiton, which he obligingly dedicated to me*{|—this 
being the first discovery of the genus in Secondary strata, although 
their probable existence in strata of that age was some time 
before predicted by him **. 
In 1852, M. Terquem added a new link to the chain uniting 
the palzozoic Chitons to those of the present epoch, by the 
discovery of a new species (C. Deshayesii) in the middle Lias of 
Thionvillet+. 
Finally, M. F. A. Roemer described and figured in 1855 a new 
* Ann. & Mag. of Nat. Hist. 1844, vol. xiv. p. 381. 
T Monogr. of the Permian Foss. of England, Pal. Soc. 1849, p. 202. 
{ Enumeratio Molluse. Sicil. t. ii. p. 85. 
§ Synopsis of the Silur. foss. of Ireland by Sir R. Griffiths, p. 74; and 
Quarterly Journ. of Geol. Soc. of London, vol. iii. pp. 48, &e. 
|| Monog. of the Crag Mollusca, pt. 1. pp. 185, &e. Besides these three 
species, Mr. Wood had also announced three others, which he considered 
to be new, in his Catalogue of Crag Mollusca published in 1842 (Ann. & 
Mag. of Nat. Hist. vol. ix. p. 460); but these he appears to have since 
abandoned. 
{! Mém. de la Soc. Linn. de Normandie, t. viii. pp. 156, &c. 
** Descript. des Anim. foss. du terr. carb., p. 321. 
Tf Bullet. de la Soc, Geol. de France, 2™° sér. t. ix. pp. 386, ete. 
