218 CHITONID.E. 



species resemble punctures, and produce a latticed ap- 

 pearance. 



It is the C. albus of Pulteney and Montagu (but not 

 of Linne), C. alveolus of Sars, and probably C. tubercu- 

 latus of Leach's ' Mollusca of Great Britain/ 



(ol-s-b- 5. C. CINE'REUS*, Linne. 



C. cinerea, Linn. S. N. p. 1107. C. asettus, F. & H. ii. p. 407, pi. lix. 

 f. 1, 2, and (animal) pi. A A. f. 5. 



BODY broadly oval, brownish-yellow, orange, or of a some- 

 what tawny fleshcolour : mantle thin : girdle rather narrow, 

 covered with small oval, rather shiny, yellowish-white or 

 darker- coloured granules, which lie one upon another in a thick 

 heap ; margin closely fringed with sharp whitish spines : head 

 semicircular, surrounded by a narrow hood : mouth forming 

 when at rest a transverse and concentrically wrinkled slit ; but 

 when open and showing the teeth, it becomes circular : gills 

 pale brownish-yellow ; only from 6 to 10 of the plumes or 

 leaflets nearest the tail on either side are visible, the others 

 being convoluted and withdrawn : foot oval, broader in front, 

 and margined by a pinkish line : vent short and tubular. 



SHELL compressed : plates as in C. cancellatus, but less solid 

 in proportion to the size ; lateral compartments indistinct : 

 sculpture similar to that of the last species, although much 

 finer and never exhibiting a punctured or cancellated appear- 

 ance : ridge slight, more or less conspicuous : colour pale yel- 

 lowish, often irregularly streaked lengthwise with dark lines, 

 and sometimes having a transverse mark of the same hue on 

 the lateral compartment near the beak in each plate : beaks 

 small: inside porcellanous, streaked in the middle like the 

 outside, displaying the leaf-like shoulders described in C. can- 

 cellatus ; margin not notched, but crenulated in the same way 

 as in the last two species. L. 0'5. B. 0-35. 



Var. Rissoi. Shell of a uniform pale yellowish colour. 

 C. Rissoi, Payraudeau, Moll. Cors. p. 87, pi. iii. f. 3, 4. 



HABITAT : Stones, and old shells (especially oysters) , 

 everywhere in the laminarian, coralline, and deep-sea 



* Ash-coloured. 



