223 CHITONIDiE. 



foot lanceolate, truncated in front, and broader towards the 

 tail, which is bluntly pointed. 



Shell somewhat convex: plates broad, rather solid and 

 opaque, without lustre ; lateral compartments scarcely (if at all) 

 raised, but marked by a slight ridge which extends on each 

 side from the beak to the front corner : sculpture like shagreen, 

 composed of not very small oval flattened granules, which are 

 arranged in two indistinct sets of rows, one lengthwise on the 

 middle compartment, and the other nearly at a right angle on 

 the lateral compartments from each side to the beak : ridge 

 distinct and prominent: colour various, forming different 

 combinations of yellow, reddish-brown, and green, often mot- 

 tled, or the plates are party-coloured, seldom of the same 

 hue throughout : heahs strong, prominent, and conspicuous : 

 inside porceUanous, with frequently a greenish tinge in the 

 middle, displaying broad leaf-like shoulders on all the plates 

 except that which covers the head ; the terminal plates often 

 exhibit white lines which radiate outwards, and represent so 

 many segments : notches deep, 8 on the head-plate, 10 on the 

 tail-plate, and 2 on each of the other plates, making altogether 

 30, besides occasionally an intermediate and slighter notch. 

 L. 0-6. B. 0-4. 



Habitat : Under stones below high water of neap tides 

 on all our coasts ; common. It is diffused everjrwhere 

 throughout the North Atlantic from Faroe (Landt) and 

 the Loffoden Isles (Sars) to Mogador (M'Andrew) . In 

 the North Sea it seems to frequent deeper water ; Asb- 

 jornsen and other writers on the Scandinavian Mollusca 

 give depths varying from 2 to 40 f. According to Gould, 

 a single specimen was found on the coast of Massa- 

 chusetts ; and the C. dentiens of that author, from 

 Vancouver's Island, appears to be undistinguishable 

 from our shell. 



This Chiton uses the under side of the head, as 

 well as the foot, in crawling. From one specimen that 

 I was observing on the 3rd of June 1864, a thin 

 stream of milky fluid issued, immediately beneath the 

 anal tube, at short intervals for about two minutes ; the 



