1865.] H. WOODWAED SILtJRIAK CIHRIPEDE. 487 



symmetrical or bilineal rows of plates being unknown (see Plate XIY. 

 fig. 6). 



More than 200 species are known, occurring in all climates 

 throughout the world, from low water to 25 fathoms ; and it is 

 interesting to find that upwards of forty species of Chitons are 

 recorded by palaeontologists in a fossil state, extending back in time 

 to the epoch of the Lower Silurian. 



During the past month I have had my attention drawn by Messrs. 

 E. J. Hollier and Charles Ketley to the two species of fossil Chitons 

 which were described and figured by M. L. de Koninck (' Bidletins 

 de I'Academie Royale des Sciences, &c., de Belgique,' 26°"^ annee, 

 2""= ser. t. iii. 1857*, p. 199, pi. 1. fig. 2), and are from the " Wen- 

 lock Shale " and Limestone of Dudley. The only specimens then 

 known were in the cabinet of Mr. John Gray, of Hagley, and are 

 now in the British Museum. The species are named respectively 

 Chiton Grayanus and G. Wrightianus ; but it is to the last of these 

 that I wish to direct attention. I have already stated the prevail- 

 ing characters of the valves of the genus Chiton, namely, that they 

 never exceed eight in number, that the series is always unilinear, 

 and that the sides of the valves are symmetrical and divided into 

 three areas. 



From the specimens furnished me by the kindness of the before- 

 mentioned gentleman, I am now able to state that the so-called 

 Chiton Wrightianus of M. de Koninck is not a Chiton, seeing that 

 it does not conform to any one of the above characters ; and scanty 

 as was the material at the disposal of M. de Koninck, I am enabled 

 to prove from the very specimen on which the species was founded 

 and the actual figure which he has published, that it is not a Chiton, 

 but a Cirripede. 



The specimens show, 



1st. That Chiton Wrightianus had probably as many as four 

 roAVS of plates. 



2ndly. That the two sides of each principal row of plates are un- 

 symmetrical, and are somewhat different both in form and sculpture. 



3rdly. That the series exceeds eight in number. 



4thly. That the plates have a uniformly sculptured surface, and 

 are not divided into three areas as in Chiton proper ; and, 



5thly. That the separate plates arc without lateral processes 

 (apophyses). 



In M. de Koninck's plate is given a figure of the original speci- 

 men, which consists of two detached plates embedded in shale 

 (Plate XIV. fig. 1 a). In this figure (fig. 2 a, op. cit., reproduced in 

 our plate, fig. 1 h) the plates are seen to be unsymmetrical ; but in 

 the restoration of the series which he gives (fig. 2 c.) they are 

 represented as symmetrical, and the series is completed with termi- 

 nal plates to match. 



His description is as follows : — 



* M. de Koninck's paper, with the original figures reproduced, appeared in 

 the 'Annals and Magazine of Natural History,' ser. 3, vol. vi. p. 91. IVanslatcd 

 by W. H. Baily, Esq., F.G.S., &c. 



