VOL. XXXIV, No. 402” JUNE, 1900 
FHE 
AMERICAN 
NATURALIST 
A MONTHLY JOURNAL 
DEVOTED TO THE NATURAL SCIENCES 
IN THEIR WIDEST SENSE 
CONTENTS 
The Neurone Theory in the Light of Recent Discoveries 
Professor G. H. PARKER 457 
Variationin the Venation of Trimerotropis . Professor JEROME McNEIL 471 
Notes on the Mammals of Prince Edward Island . ROBERT T. YOUNG 483 
The Cactus Bees; Genus Lithurgus . Professor T. D. A. COOKERELL 487 
The Advance of Biology in 1897  . . Professor C. B. Po pis 489 
On the Interpretation of Unusual Events in Geologic Reco 
Illustrated by Recent Examples Professor F. T SIMONDS 495 
Synopses of North-American hinini X. The Oxyrhyn- 
Oxystomatous Crabs of North America. MARY J. RATHBUN 503 
Reviews of Recent Literature: Anthropology, The Races of Man — 521 
Zoólogy, The White-Fish of Lake Chapala, Evermann on Species and 523 
Subspecies, Smith on the Fishes of Woods Holl, Eigenmann on Blind 
Vertebrates, Microbdella biannulata, Locomotion of Solen nomya, ze 
Bones, Otocysts of the Heteropods, Capillaries and Sinusoids, Villi 
the Mammalian Intestine, Notes 
IX. News 529 
X. Note on Cestode Nomenclature  . : ; . Professor H. B. WARD 533 
XI. Publications Received 534 
B d dadia . 
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