PATELLIM;. 251 



The other British Chitons are 



C. DISCREPANS, Brown. 



C. discrepans, Brit. Moll. ii. p. 396, pi. 58. f. 4. 

 C. HANLEYI, Bean. 



C. Hanleyi, Brit. Moll. ii. p. 398, pi. 62. f. 1 & f . 1 a, 5th valve. 

 C. RUBER, Linnaeus. 



C. ruber, Brit. Moll. ii. p. 399, pi. 59. f. 6 ; (animal) pi. A. A. f. 6. 

 C. L.EVIS, Pennant. 



C. Itevis, Brit. Moll. ii. p. 411, pi. 58. f. 3. 

 C. CANCELLATUS, SoWCrby. 



C. cancellatus, Brit. Moll. ii. p. 410, pi. 59. f. 3. 

 C. ALBUS, Linnaeus. 



C. albus, Brit. Moll. ii. p. 405, pi. 62. f . 2 & f . 2 a, 5th valve. 

 C. MARMOREUS, Fabricius. 



C. marmoreus, Brit. Moll. ii. p. 414, pi. 58. f. 2, and pi. 59. f. 4. 



We have seen none of the above alive. The C. discrepans 

 is not strictly British; it inhabits the French coasts and 

 Channel Islands. We are almost of opinion that it is distinct 

 from the C. fascicularis. 



PATELLID^l. 



In my observations on the Chitons, I have stated that they 

 would be incomplete unless naturalists were afforded the means 

 of comparing them with the Patelloid genera, to which they 

 exhibit the closest alliance so much so, that no particular 

 violence would be done to natural position if they were re- 

 garded as a genus of the Patellida. I now supply the mate- 

 rials for comparison, which I think will confirm my views of 

 the position of the Chitons as true mollusca, and be in some 

 other points interesting to the readers of this branch of 

 zoology. 



The Patelloida, as I designate them, are the Fissurellidce, 

 Calyptraadae, and Haliotida of authors, which families I shall 

 dispense with, retaining the derivative genera as components 

 of the Patellida ; these, with the addition of Patella, Acmea, 



