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. sent 106 FEBRUARY 18, 1922 
OCCASIONAL PAPERS OF THE MUSEUM OF 
ZOOLOGY 
UNIVERSITY OF MICHIGAN > 
ANN ARBOR, MICHIGAN PUBLISHED BY THE UNIVERSITY 
Weed Wine [Ljo2 
THE MOLLUSCA COLLECTED BY THE UNIVERSITY 
OF/ MICHIGAN WALKER) EXPEDITION, IN 
‘SOUTHERN VERA CRUZ, MEXICO. /I 
By H. Burrincton BAKER / 
ie 
INTRODUCTION 
The specimens on which this paper is based were collected 
by the University of Michigan-Walker Expedition, during six 
weeks (July 10 to August 20) in the summer of 1910. The 
expedition consisted of Alexander G. Ruthven and his wife, 
Florence HP Ret wie para poruCular attention to the 
amphibians and reptiles, and the writer, who was primarily 
interested in mollusca. 
The work of identification and description was made pos- 
sible by the Academy of Natural Sciences of Philadelphia, 
which generously put at my disposal its extensive collections 
and exhaustive library. As a result, any credit that this paper 
may deserve is largely due to Dr. H. A. Pilsbry, whose con- 
