412 CHITONID^. 



vol. viii. p. 21. — Turt. Conch. Diction, p. 33. — Lowe, Zoolog. 

 Journ. vol. ii. p. 97, pi. 5, f. 1. — Fleming, Brit. Animals, p. 

 290. — Brit. Marine Conch, p. 129. — Wood, General Conch, p. 

 22. — Sowerby, Conch. Illust. Chiton, species 7, f. 101, 102. — 

 Philippi, Moll. Sicil. vol. i. p. 107, pi. 7, f. 4 ; vol. ii. p. 83.— 

 Reeve, Conch. Icon. vol. iv. Chiton, pi. 26, f. 125. 

 Chiton marginatus, Pulteney, Hutchins, Hist. Dorset, p. 25 (probably). — 

 Maton and Rack. Trans. Linn. Soc. vol. viii. pi. 1, f. 2. 

 — Rackett, Dorset Catalog, p. 25, pi. 1, f. 2 (probably). 

 — Lam. Anim. s. Vert. (ed. Desh.) vol. vi. p. 492 (in part 

 only). 

 „ achatmus, Brown, Illust. Conch. G. B. p. 65, pi. 21, f. 4, 12, 13, 15. 

 „ corallinus, Risso ! H. N. Europe Mer. vol. iv. p. 268 (fide Philippi). — 

 LovSn, Index Moll. Scandinav. p. 28. 



Considerable doubt exists as to this being the species 

 actually intended by Pennant under the epithet Icevis, 

 but as an unbroken chain of traditional authority has 

 sanctioned the identification, and his brief diagnosis and 

 wretched figure will not agree better with any other 

 British Chiton, we have, although with some hesitation, 

 attributed to that author the merit of having founded 

 the species. Its peculiar margin enables even the most 

 casual observer to distinguish it at a glance from its native 

 congeners. 



The shape ranges from oval to produced elliptical, 

 and the shell is much, and rather suddenly, elevated 

 dorsally, assuming in the more typical and laterally com- 

 pressed examples a more angular appearance, from the 

 plates being more or less flattened (instead of convex) 

 at the sides. The middle portion of the posterior or 

 externally visible edge of the valves is, in the young, 

 decidedly beaked, in the middle-aged specimens but slightly 

 so, whilst, in aged individuals, owing to the frequent dorsal 

 erosion at that stage of growth, this mucronation becomes 

 obscure or obsolete ; the lateral portions have a tendency 

 to slope backwards. The general colouring is red or 



