CLASS III. GASTEROPODA. ORDER II. CYCLOBRANCHIATA. 7 
Order Il. GASTEROPODA CYCLOBRANCHIATA. 
Branchize subfoliacee aut subpyramidate, symmetrice, plus minusve. 
contigue, sub margine pallii in serie regulari circumposite. 
The Chitones and Patelle were associated together by Cuvier under 
the above title, on account of their respiratory organs being placed in a 
regular circle round the body. This arrangement of the branchial appa- 
ratus has, however, been denied by De Blainville with respect to the 
latter, it being his opinion that it is situated in a cavity at the back of 
the neck, and that the Patelle therefore belong to the next order, Cer- 
vicobranchiata. But Cuvier, upon re-examining their anatomy, refuses 
to admit this opinion, for, after giving it every consideration, he arrives 
at the following conclusion: ‘‘ a m’a eté impossible de le découvrir, ni d’y 
voir dautre organe de la respiration que le cordon de feuillets qui regne 
tout autour sous le rebord du manteau.”’ The Chitones are altogether dis- 
missed from the Mollusca by the learned author of the ‘ Manuel de Mala- 
cologie ;’ he associates them with the Lepades in a new and particular 
subkingdom, Malentozoaria (Latiné Molluscarticulata), under the impres- 
sion that both are intermediate in their organization between the Mol- 
lusca and the Articulata (Crustacea, e.g.). The title of Cyclobranchiata is 
employed by De Blainville in reference to the Doride, &c. (naked mol- 
lusks), but these are the Nudibranchiata of Cuvier, and must therefore 
not be confounded with the present order. Gray appears to have escaped 
all controversy by including both under the new title of Gymno- (Latiné 
Nudi-) branchiata, a name which merely denotes that the branchiz are 
naked, without particularizing their position ; he thus retains the Doride 
and Chitonide in the same order. It is now evident that zoologists are 
pretty well agreed as to the propriety of Cuvier’s arrangement, although 
some of the animals which are thus associated have a multivalve shell, 
others an univalve, the very characters that were selected by Linnzus as 
