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The American Midland Naturalist 
PUBLISHED BI-MONTHLY BY THE UNIVERSITY 
' OF NOTRE DAME, NOTRE. DAME, INDIANA. 
VOL. IV. MAY, 1915. NO. 3. 
THE NAIADES OF MISSOURI. 
nsenian Insane 
Sat 
JUN 14 1920 
4 
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BY WILLIAM I. UTTERBACK. 
(Plates i—xxvii1.) New Series. 
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Introduction. : 
After some years of intensive studies in the field, library and 
laboratory an attempt is made to give a catalogued account of 
the Nazades, or Fresh-water Mussels, of Missouri. Most of the 
data for this descriptive and illustrated catalogue have been 
collected through extensive, personal surveys of the most import- 
tant streams and lakes of the State and now the typical anato- 
mical and shell material frem the different localities are pre- 
served in the writer’s laboratory. No literature of any conse- 
quence, dealing with the Nazades of Missouri, had been produced 
until the author of this paper made a preliminary report on 
‘The Mussel Resources of Missouri.’ ‘This was, however, a 
government report, published for economic purposes, the detailed 
account of the scientific observations of which will not appear 
until a later date. 
The plan of classification, based on anatomical structures, 
notably those of marsupial characters, has been carefully followed 
in this work. The many changes in the nomenclature of this 
catalogue from that of the Simpsonian system are due especially 
to the recognition of Lindahl’s orthographic modification and of 
the wise scheme of taxonomy for the Nazades begun by Sterki 
(1906) and well consummated by Ortmann (1912); and also to the 
acceptance of Rafinesque’s priority as recently revived by Mr. 
Frierson and ‘accepted by Dr. Ortmann. The writer believes 
that the ultimate taxonomic system will be based far more upon 
the anatomical structure of juvenile and adult than upon their 
shell characters from the fact that the soft parts are more constant 
