1865.] IT. WOODWARD SILrRIAI^^ CIKRIPEDE. 489 



and U)la), the principal part of the animal's body was lodged in the 

 peduncle*. As to the numbers of rows of plates it would be rash 

 perhaps, with our present materials, to attempt a restoration, but 

 Mr. Ketley's specimen (Plate XIV. figs. 1, e,f) seems to require only 

 two rows of large plates to complete its circumference. In the 

 Cirripedia, the number of plates is extremely variable in different 

 genera, as is indeed the case in all the Crustacea. 



It is probable that the two broad rows of intersecting plates 

 corresponded with the lateral rows of plates, and the two minute 

 rows with the carinal and rostral series along which the specimen 

 seems more readily to have divided, as in the case of Loricida, 

 to which Mr. Darwin refers {ib. p. 85). But, until more perfect 

 materials arrive, we must rest content with being enabled to affirm 

 that it is a Cirripede, and not a Chiton. 



I trust this imperfect description will be rendered comprehen- 

 sible by the assistance of the numerous figures. 



In the examination of fossil Chitons it is quite unsafe to trust 

 to figures alone ; I therefore will not ventm-e to throw a doubt 

 upon the identification of Chiton Loftusianus or of Helminthochiton, 

 although it would be well to examine the actual specimens. Chiton 

 Grayanus appears to be a true Chiton. Chiton Wrightianus being no 

 longer a Chiton, but a Cirripede, I beg to propose for it the generic 

 appellation of Turrilepas (from turris an " armed tower," and lepas, 

 Linnseus's name for the group to which it is now transferred). 



EXPLANATION OF PLATE XIV. figs. 1-6. 



{Illustrative of a neio Silurian Cirripede.) 



These figures are of the natural size, except when otherwise stated. 



Fig. la. Turrilepas {Chiton) Wrightii, H. W. The tyjDe specimen from the 

 Gray Collection, now in the British Museum. 

 1 h. Figure of the same, copied from M. de Koninek's plate {op. cit.). 

 1 c. T. Wrightii, Wenlock Shale, Dudley, from Mr. E. J. HoUier's collection. 



1 "'• jj J) )j 



1 e. „ „ from Mr. Charles Ketley's coUeclion. 



\f. . (view of base of same). 



\g.\ from the collection of Mr. S. AUport, of Birmingham. 



1 h.\ from the Wenlock Limestone, Wren's Nest, Dudley, from 



the collection of Mr. H. Johnson, Dudley. 

 \i,\1c,\l. Enlarged views of the three forms of plates seen in specimens 



Ic, e,f, h, and marked i, Jc, I, respectively. 



2. Loricula pulchella, G-. B. Sowerby, jun. (Darwin's Fossil LepadidcB, 



Pal. Mon. t. 5. fig. 1), Lower Chalk, Kent. 



3. Tergum of Pollicipes fallax, Upper Chalk, Norwich. Darwin, Mon. 



Foss. Lepadida3, t. 4. fig. 8. 



4. ScalpeUum ornatum, recent. Darwin on LepadidcB (Ray Soc.) t. 4. fig. 1 



5. Tergum of Balanus tintinnahiilum (recent). 



6. Chiton fulvus (recent), Coruna Bay. 



* See Dai'win's fossil Cirripedia (Mon. Pal. Soc. 1861), " Observations on 

 Loricida^^ p. 82. 



t Fi"-s. g and h represent two very beautiful specimens of Turrilepas re- 

 ceived subsequent to the reading of this paper before the Society. 



