CHISMOBRANCHIATA. Bl. The second order of the first section of Paracephalophora Monoica, Bl. Those Mollusca belonging to this order which have shells, have them either internal or external, but always scutiform, with depressed spires and wide, haliotoid, oblique apertures, without a columellar lip properly so called. This order partly answers to the family MACROSTOMATA, in the system of Lamarck. It contains the genera Coriocella, Sigaretus, Cryptostoma, Oxinoe, Stomatella and Velutina. CHITON. Auct. ([Greek: chiton], an integument.) _Fam._ Phyllidiana, Lam. _Class_, Polyplaniphora, Bl.--_Descr._ Oval, consisting of eight arched valves arranged in a series across the body of the animal and fixed in the skin which forms a rim around them, sometimes scaly, spinose, or rugose, sometimes smooth.--_Obs._ The genus Chiton, commonly called "Coat of Mail," from its resemblance to jointed armour, remains to the present day in exactly the same state with regard to its boundaries as that in which Linnæus found it, and in which he left it. That illustrious Naturalist placed it among the multivalves in his purely Conchological system, although the animal is totally different from the Cirripedes. The shells are prettily marked, and are found attached to the rocks in all seas of Tropical and Southern climates, but fossil species are almost unknown. Fig. 227, C. Spinosus. The genus is divided by Guilding into Chiton, Canthopleura, Phakellopleura, Chitonellus and Cryptoconchus. Zool. Journ. XVII. p. 27. The author of this manual has lately attempted a revision of this interesting but neglected genus, and has given a catalogue of all the species hitherto known, as far as they could be identified among the confused mass of synonyms and descriptions to be found in the works of various Conchological writers. This catalogue is to be found in his Conchological Illustrations, and refers to figures of 102 species, 92 of which are contained in parts 38 to 45, and 159 to 176. CHITONELLUS. Lam. (From _Chiton_) Separated by Lamarck from Chiton, on account of the valves being placed at a greater distance from each other, the soft integument of the animal intervening. Fig. 228, C. striatus. Philippines. CHLOROSTOMA. Sw. A sub-genus of "Trochinæ." Sw. (Trochus) of which C. argyrostoma is given as an example. Sw. Lard. Cyclop. p. 350. CHONDRUS. Hartmann. ABIDA, Leach. A genus formed for the reception of PUPA secale, Drap. Pupa Juniperi, Montague, which have plaits in the aperture. CHRYSOAR. Montf. Probably a species of ORTHOCERAS.