42 
CALIFORNIA SEA-SHELLS. 
farther northward, on the Oregon coast, and 
even about Sitka. And here we may say that 
a large number of the descriptions contained in 
this little book apply as well to the shells of Or- 
egon and Washington Ty., as to California. Some 
of the species are much finer on the northern 
coasts, than on our own. Tonicia lineata , Wood, 
Painted Chiton, (not figured), is a small species, 
about an inch in length, with smooth and naked 
mantle, and eight polished valves, beautifully 
striped and painted. The chief color is orange, 
and the markings are white and dark reddish 
brown. Within, the valves are white, shaded 
with orange. Living specimens are found at 
very low water, but single red valves are often 
washed ashore. 
White, butterfly - shaped shelly plates may 
often be picked up among the rocks, from one to 
two inches in length ; and from their singular 
appearance they have been called “ Butterfly 
Shells.” They are, really, single valves washed 
from the dead body of the Giant Chiton, Cryp- 
tochiton Stelleri , Midd., a huge mollusk some- 
times found entire. It is six inches in length, 
and three in breadth ; the white valves are 
wholly concealed beneath the reddish brown, 
hard, gritty mantle, which covers the whole 
back of the animal. Thus the mystery of the 
“Butterfly Shells” is explained, and they be- 
come of more interest, since wc know their true 
origin. 
The little shell shown in Fig. 2, PI. XI, be- 
longs to the sub-class which also includes the 
Bubble-shells, and the Sea-slugs, or naked mol- 
