CONCHOLOGY. 95 



C. squamosus. The scaly Chiton. PI. 1, fig. 1. 



Depressed, valves large, carinated, well imbricated ; the 

 interstices offering well-marked lateral spaces ; the border 

 of the mantle regularly scaly. 



C. marginatum. The marginated Chiton. PI. 1, fig. 2. 

 Valves carinated and projecting over each other ; finely 

 shagreened, with a dusky reddish-brown margin. 



C. fascicular is. The fasciculated Chiton. PI. 1, fig. 3. 



Valves more narrow, imbricated, without distinct spaces ; 

 lateral parts of the skin naked or hairy, but always provided 

 with silky or hairy tufts disposed in pairs between the junc- 

 tions of the valve. 



C. spinosus. The spiny Chiton. PI. 1, fig. 4. 

 Shell beset with long, thin, curved, tubular, hairy, black- 

 ish spines. 



4. Patella. The Limpet or Dishlike Shell. Forty-five 

 species. 



The Patella of Linnaeus was divided by Lamarck into 

 several distinct genera, and now comprehends only such 

 shells as are of a conical form, with an imperforated summit. 

 The anterior is that part to which the summit inclines, and 

 is always more narrow than the posterior part. 



It derives its name from its resemblance to a little dish ; 

 the colour and structure are various ; some are smooth, 

 others granulated, and many are covered with elevated tu- 

 berculated ribs. The exterior is sometimes of a pale fawn 

 colour, and the interior of a bright pink ; some have a sil- 

 very hue, but the more general colour is bluish white or 

 light brown. 



This genus of shells is very numerous in all seas, but 

 chiefly in hot countries, where they are found of a larger 

 size ; they generally adhere by their base to rocks, stones, 

 and marine substances, from which it is difficult to detach 

 them. 



