VoL. XXXV, NO. 412 APRIL, 1901 — 
THE 
AMERICAN = 
NATURALIST =] 
A MONTHLY JOURNAL 
DEVOTED TO THE NATURAL SCIENCES 22 
IN THEIR WIDEST SENSE ; 
CONTENTS 
E-A Theory of the c and Evolution of the Australian ; 
Marsupialia  . B, ARTHUR seNsIEY E 
II. A creme study of Variation in ‘the smaller North- PEE ED 
IIL A New bri for PR Te. eee Dr, aak quic 
IV. Synopses of North-American Invertebrates. E Heo 
—— hes 
T e. v. tue 2 
mies Publi ul i 
Life, Notes — uisi. Traquair's | Presidential | Address, Welais 
Fossils from Eastern Siberia, Tht DUM. Paleozoic c Fauna of Pium 
ly R s, and De 
