CHITON. 11 



Shell very small, rounded at the back, and contracted at the 

 margin, so as to give it somewhat of a cylindrical form ; 

 Schroeter says, it appears smooth to the naked eye, but when 

 examined with a microscope proves to be rough like shagreen, 

 with minute raised dots. 



albus, 29. Shell with eight smooth white valves, 

 of which the first is notched on the hinder 

 edge. 



Chiton albus. Linnaus Syst. Nat. p. 1107. Mutter J eta 

 Nidros. ii. p. 54. Chemnitz, viii. p. 290. t. 96. f. 817. 

 Schroeter Mini. iii. p. 500. Gmelin, p. 3204. Dorset 

 Catalogue, p. 25. t. 1. f. 3. Montagu Test. p. 4. Ma- 

 ton and Racket, in Lin. Trans, viii. p. 22. t. 1. f. 4. 

 Wood's Conch, p. 20. 

 Inhabits the Northern Ocean. Mutter. Coasts of Britain, 



adhering to shells and Ulvae. Pulteney, &c. 

 Shell varying from the size of a grain of wheat to about three 

 quarters of an inch long, oval, not carinated or very slightly 

 so, and the first valve is notched on the hinder edge. 



marginatus. 30. Shell with eight carinated valves, 

 and a serrated reflected margin. 



Chiton marginatus. Pennant Zool. iv. p. 71. t. 36. f. 2. 

 Gmelin, p. 3 L >06. Dorset Catalogue, p. 25. t. 1 . f. 2. 

 Montagu Test. p. 1. Maton and Racket, in Lin. Trans. 

 viii. p. 21. 1. 1. f. 2. Wood's Conch, p. 21. t. 3. f. 4. 

 Chiton, No. 17- Schroeter Einleitung, iii. p. 508. 

 Argenville, t. 25. f. M. 



Variety. With only seven valves. 



Chiton septemvalvis. Montagu Test. p. 3. and Script, p. 1. 

 Chiton discors. Maton and Racket, in Lin. Trans, viii. p. 

 20. 



Inhabits the coasts at Dieppe. Argenville. Coasts of Bri- 

 tain ou oysters and other shells. Pennant, fyc. 



Length about half an inch ; and the breadth is rather more 

 than half the length. The shell to the naked eye is smooth, 

 but under the microscope appears like shagreen, and the 

 colour is dingy brown or reddish. The late Mr. Montagu, 

 whose death every admirer of natural history must deplore, 

 has, in the Supplement to his admirable work on British 

 Shells, expressed his opinion, that C. septemvalvis is only an 

 accidental variety of this species. 



