MOLLUSCA. 
67 
Phyllidiacea.] 
colour various, dark chocolate-brown, burnt terra-sienna, or 
yellowish-white, with clouds, streaks, or spots. Length not 
quite half an inch; breadth somewhat more than half its 
length. 
This shell has much the general appearance of the former 
species, but its marginal teeth sufficiently characterise it as dis- 
tinct. 
Found at Oban and Appin, on the Argyleshire coast, but is 
very rare. The handsome specimen from which I drew fig. 21, 
was sent me by Captain Carmichael. 
Section III. — Marginal ligament smooth. 
13. Chiton l^vigatus, pi. XXI, f. 1 and 16. 
Chiton lahis, First Ed., pi. 35, f. 1 and 16; Chiton Iceviga- 
tus, Fleming, Edin. Ency., p. 103; Lowe, Zool. Journ., II, p. 
103, pi. 5, f. 6, 7. 
Shell oblong, broad, somewhat wider behind than before, and 
slightly carinated; valves smooth, shining, and beaked, with 
minute granulations; marginal ligament quite smooth, simple, 
with a very short and indistinct fringe; first valve with nine 
broad teeth, and the terminal one with eight broad teeth; 
colour generally dark reddish-olive, and mottled with a paler 
hue, in others approaching to dark slate-colour, and sometimes 
reddish-brown. Length somewhat more than an inch ; breadth 
three-fifths of its length. 
In the character of the marginal teeth, this shell approaches 
that of C. ruher. 
Found by Mr. Lowe, at Oban, Argyleshire, on the under side 
of loose rocks, whiph are only uncovered at Spring tides, about 
fifty yards south of the Custom House, and also at Appin, by 
Captain Carmichael, who sent me the specimen from which fig. 
1 was drawn. Fig. 16 was taken from a specimen found by my 
late friend Mr. Hancock, of Newcastle-upon-Tyne, below Tyne- 
mouth Castle, in 1809 ; so that he was the discoverer of the 
species. It was found plentifully in Zetland and Loch Broom, 
by Dr. Fleming. 
Section IV. — Doubtful species. 
14. Chiton discors. 
Chiton discors, Maton and Rackett, p. 20; Chiton septem- 
valvis, Montagu, p. 3. 
“With seven carinated valves, strongly beaked; the five 
middle ones divided transversely from the anterior base to the 
beak, the hinder compartment very fine shagreen, the other 
very smooth, or faintly striated transversely; the extreme valve 
at each end rufous-brown, the rest generally dark cinereous; 
beaks frequently rufous ; margin moderately broad, and finely 
reticulated ; shape of C. Icevis. Length half an inch. 
“ Found in Salcomb Bay, but rare.” — Montagu. 
Whether this is a distinct species, it is difficult to determine; 
although I think in all probability it is, as well as the following 
species, lusus natures. Montagu, in his Supplement, says, “we 
are inclined to believe this an accidental variety of C. mar- 
ginatus.” 
15. Chiton quinquevalvis, pi. XXI, f. 22. 
Chiton quinquevalvis, First Ed., pi. 35, f. 22. 
Shell oval, carinated, of a reddish-gray ; with five consider- 
ably beaked valves, covered with strong, shagreen-like papilli ; 
valves divided on each side by a deep groove, inclining obliquely 
from the flat edge towards the beaks, where the grooves termi- 
nate; margin rather broad, covered with extremely fine, irregu- 
lar, shagreen-like papilli, with the edge ciliated. Length three 
and a half eighths of an inch ; breadth three-eighths. 
Found at Tenby, by General Bingham. 
