PATELLID. 251 
The other British Chitons are— 
C. pIscREPANS, Brown. 
-C. discrepans, Brit. Moll. ii. p. 396, pl. 58. f. 4. 
C. Hanteyi, Bean. 
C. Hanleyi, Brit. Moll. u. p. 398, pl. 62. f. 1 & f. 1 a, 5th valve. 
C. ruBerR, Linnzeus. 
C. ruber, Brit. Moll. ii. p. 399, pl. 59. f.6; (animal) pl. A. A. f. 6. 
C. travis, Pennant. 
C. levis, Brit. Moll. n. p. 411, pl. 58. f. 3. 
C. cANCELLATUS, Sowerby. 
C. cancellatus, Brit. Moll. ii. p. 410, pl. 59. f. 3. 
C. atsus, Linneus. 
C. albus, Brit. Moll. ii. p. 405, pl. 62. f. 2 & f. 2 a, 5th valve. 
C. marmorevs, Fabricius. 
C. marmoreus, Brit. Moll. u. p. 414, pl. 58. f. 2, and pl. 59. f, 4. 
We have seen none of the above alive. The C. discrepans 
is not strictly British; it mbhabits the French coasts and 
Channel Islands. Weare almost of opimion that it is distinct 
from the C. fascicularis. 
PATELLID. 
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 Patellide. 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 pomts interesting to the readers of this branch of 
zoology. 
The Patelloida, as I designate them, are the Fissurellide, 
Calyptreade, and Haliotide of authors, which families I shall 
dispense with, retaining the derivative genera as components 
of the Patellide ; these, with the addition of Patella, Acmea, 
