VOL. XLIII, NO. 514 S 



OCTOBER, 1909 



THE 



AMERICAN 

 NATURALIST 



A MONTHLY JOURNAL 



Devoted to the Advancement of the Biological Sciences with 

 Special Reference to the Factors of Evolution 



CONTENTS 



I. The Non-muscular Articulations of Crinoids. AUSTIN HOBART CLARK, 

 n. On Some Dinichthyid Armor Plates from the Marcellus Shale. BURNS 

 SMITH 



III. Are Species Realities or Concepts only. Professor J. H. POWERS. 



IV. Shorter Articles and Discussion : A Light Weight, Portable Outfit for 1 



of Caraolestes with Polyprotodonta and Diprotodonta. Pauline 



V. Notes and Literature : Comparative Psychology — Bohn's " The Birth of Tn 



ligence": Professor H. S. J rnnin*,-. Mammalogy -0 ?l n„,r~ i: 



the Mice of the Genus Peromyscus, Dr. J. A. AlXEN. Leo Errara, Profei 



THE SCIENCE PRESS 

 LANCASTER, PA. GARRISON, N. Y. 



NEW YORK: SUB-STATION 84 



