CHITON. 403 



us to identify the clearly defined shells of Lowe with the 

 previous obscure ones of our native authors. As in the 

 present case it is absolutely impossible to say what Pen- 

 nant intended by his Chiton marginatus, we have decided 

 upon using the prior name of cinereus, although Linneeus 

 has so inadequately defined his species, that, despite our 

 certainty, from actual inspection of his cabinet, we should 

 otherwise have avoided using that appellation. Moreover, 

 the essential characters were not clearly indicated until its 

 publication by Mr. Lowe as C. cinereus. 



This is the commonest of our British Chitons, and by 

 far the most variable in diversities of colouring. It is 

 of a somewhat produced ovate shape, moderately elevated, 

 subcarinated, or rather subangulated above, and with the 

 outer edge of each valve mucronated or slightly beaked in 

 the middle, and but moderately incurved laterally. Olive 

 is, perhaps, the most prevalent tint, but no stress can be 

 laid upon colour in this species, since some are orange, 

 some nearly white with patches of a chocolate hue, some 

 crimson red with white markings, some flesh colour with 

 one or two of the valves of a madder-lake, &c. ; many of 

 the greenish varieties are waved with faint brown lines, or 

 speckled with paler dots, and the dorsal ridge is not 

 unfrequently pallid, or else painted on either side with a 

 paler stripe : the margin is frequently, but not invariably, 

 banded or spotted with whitish, opposite the sutures of 

 the valves. The lateral areas are only indicated, for 

 the most part, by their superior elevation, and are not 

 defined by any marginal line or peculiarity of sculpture, 

 for the entire exterior is most closely shagreen ed by small 

 (often minute) depressed elongated granules, which do not 

 exhibit either a radiating or longitudinal arrangement, but 

 are approximately and somewhat concentrically disposed, 



