22 THE NAUTILUS. 
perating shells, although of course in this particular case the 
excess of CaCO; itself, may inhibit extended absorption of itself, 
or this be prevented by the presence of other compounds. In 
conclusion, I wish to express my obligation to Dr. A. E. 
Ortmann, on whose material at the Carnegie Museum these 
observations were made. 
BIBLIOGRAPHY. 
1. Hey, W. C., ‘Freshwater Shells in the Ouse and Foss.” Journal Con- 
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3. Beauchamp, W. ‘“Eroded Shelis.” Conchol. Exchange, Vol. 1, p. 50, 
1886. 
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lated to the conditions of Life.” Phil, Trans, 1889. 
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1918, 
A NEW ALASKAN CHITON. 
BY WILLIAM HEALEY DALL. 
ScHIZOPLAX MULTICOLOR Nn. sp. 
Chiton depressed, broad, wider behind than in front, maroon 
varied with white streaks, with a rather wide girdle, the surface 
of which is covered with soft bristles like those of Mopalia mus- 
cosa, among which are sparsely scattered, irregularly disposed, 
longer translucent spicules; surface of the valves minutely uni- 
formly reticulate under the lens, appearing smooth to the un- 
aided eye; the mesial suture evident, the fifth valve widest, the 
