228 CHITONID.E. 



barred with dark orange ; margin fringed with extremely 

 short yellowish spines. 



Shell convex : plates broad, solid and opaque, somewhat 

 glossy ; lateral compartments distinct, not much raised, but 

 defined by a blunt ridge which extends from the beak on 

 either side to the front corner of each plate : sculpture nearly 

 smooth to the naked eye, exhibiting under a magnifying-power 

 numerous minute and slight tubercles, which usually are more 

 conspicuous on the terminal plates and side compartments, as 

 in 0. Icevis ; the parallel lines of growth are strongly marked 

 in adult specimens: ridge indistinct: colour reddish -brown, 

 variegated or speckled with white or yellow, sometimes in a 

 zigzag or lightning fashion : beaks very strong and prominent : 

 inside yellowish, tinged with pink, showing the under side or 

 hollow of the ridge to be striated across ; shoulders long and 

 narrow : notches deep, 8 on the head-plate, 9 on the tail-plate, 

 and 2 on each of the other plates, making 29 in all, besides 

 some intermediate denticles. L. 1. B. 0*6. 



Habitat : Stones, shells, and sea-weed in the Lami- 

 narian zone, from Shetland to Scarborough (Bean) ; 

 eastern shores of Ireland, as far south as Dublin Bay 

 (Kinaghan). Fossil at Fort William (J. Gr. J.); Udde- 

 valla (Malm) . It inhabits every part of the Atlantic, 

 north of Great Britain, from Spitzbergen to Zealand, 

 and the coasts of North-east America, at depths of 

 from 7 to* 100 f. M f Andrew has recorded it as dredged 

 at Carthagena in 5-10 f. ; this appears to be the only 

 instance of a southern locality. 



According to Brown, Mr. Hancock discovered this 

 king of the British Chitons below Tynemouth Castle 

 in 1809. Laskey indicated it from Dunbar in 1811. 

 Fabricius says that it is often found in the crops of the 

 Eider-Duck and Anas spectabilis. His description of 

 the animal and shell is most admirable; and he particu- 

 larly noticed the notches on the margin of each plate 

 or valve, as characteristic of this and other species of 

 Chiton. It is stated by Middendorff that the epider- 



