The American Naturalist 



A Monthly Journal, established in 1867, Devoted to the Advancement of the Biological Sciences 

 with Special Reference to the Factor* of Organic Evolution and Heredity 



CONTENTS OF THE JULY NUMBER 



Selection Index Numbers and their Use in Breeding. 

 Dr. Raymond Pearl and Frank M. Surface. 



A Contribution to the Theory of Orthogenesis. Dr. 

 Alexander G. Ruthven. 



The " Presence and Absence " Hypothesis. Dr. George 

 Harrison Shull. 



Present Problems in Plant Ecology : Vegetation and 

 Altitude. Professor Charles H. Shaw. 



Shorter Articles and Correspondence : Pleistocene 

 Swamp Deposits in Virginia. Dr. Edward W. 

 Berry. 



Notes and Literature : Heredity — A Case of Non-Men- 

 delian Heredity. Dr. W. J. Spillman. 



CONTENTS OF THE AUGUST NUMBER 



The New Flora of Krakatau. Professor Douglas 

 Houghton Campbell. 



A Male Crayfish with Some Female Organs. Professor 

 E. A. Andrews. 



Present Problems in Plant Ecology : 



Problems of Local Distribution on Arid Regions. 

 Professor Volney M. Spaulding. 



The Relation of the Climatic Factors to Vegetation. 

 Professor Edgar N. Transeau. 



Notes and Literature : Recent Experiments on the In- 

 heritance of Coat Colors in Mice, Professor T. H. 

 Morgan. Some Experiments in Breeding Slugs. 

 Professor T. D. A. Cockerell. 



CONTENTS OF SEPTEMBER NUMBER 



Oa an Early Tertiary Land-connection between North 

 and South America. Dr. R. F. Scharf. 



Notes on the Relations of the Molluscan Fauna of the 

 Peruvian Zoological Province. Dr. William Hea- 

 ley Dall. 



Remarkable Development of Starfishes on the Northwest 

 American Coast ; Hybridism ; Multiplicity of Rays: 

 Teratology ; Problems in Evolution ; Geographical 

 Distribution : Professor A. E. Verrill. 



Shorter Articles and Correspondence : Is there a Selec- 

 tive Elimination of Ovaries in the Fruiting of the 

 Leguminosse : Dr. R. Harris. 



Notes and Literature : Ichthyology — Ichthyological Notes, 

 President David Starr Jordan. Parasitology — 

 Professor H. B. Ward. Plant Cytology— The Per- 

 manence of Chromosomes in Plant Cells, Dr. Brad- 

 ley M. Davis. 



CONTENT8 OF THE OCTOBER NUMBER 



The Non-muscular Articulations of Crinoids. Austin 

 Hobart Clark. 



On Some Dinichthyid Armor Plates from the Marcellus 

 Shale. Burnett Smith. 



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

 Powers. 



Shorter Articles and Discussion : A Light Weight, Port- 

 able Outfit for the Study and Transportation of Ants. 

 Edith N. Buckingham. Comparison of Csenolestes 

 with Polyprotodonta and Diprotodonta. Pauline 

 H. Dederer. 



Notes and Literature : Comparative Psycholoy — Bonn's 

 "The Birth of Intelligence " : Professor H. S. Jen- 

 nings. Mammalogy — Osgood's Revision of the Mice 

 of the Genus Peromyscus, Dr. J. A. Allen, Leo 

 Errara, Professor Charles E. Bessey. 



CONTENTS OF THE NOVEMBER NUMBER 



The American Toad (Bufo lentiginosus americanus 

 LeConte). Newton Miller. 



Notes on the Behavior of the Domestic Fowl. Philip B. 

 Hadley. 



Vitality of Pine Seeds and the Delayed Opening of Cones. 

 Professor W. C. Coker. 



The AflSnities of the Echinoidea. Austin Hobart 

 Clark. 



The Early Breeding Habits of Amblystoma punctatum 



Notes and Literature: Marine Biology — Papers from the 

 Tortugas Laboratory, Professor Willi am E. Eitter. 

 Experimental Evolution — Inheritance of Color in 

 Pigeons, B. B. Horton. 



CONTENTS OFTHE DECEMBER NUMBER 



The Cuticula and Subcuticula of the Trematodes and Ces- 

 todes. Professor Henry S. Pratt. 



The American Toad (Bufo lentiginosus americanus, 

 LeConte). Newton Miller. 



Observations on Copulation among Crawfishes with 

 Special Reference to Sex Recognition. Dr. A. S. 

 Pearse. 



Shorter Articles and Correspondence : Degeneration ac- 

 companying Inbreeding. Professor C. B. Daven- 

 port. A Note of the Prairie-dog Owl which Re- 

 sembles the Rattlesnake's Rattle : Dr. J. Arthur 

 Harris. 



Notes and Literature : The Causation of Sex, Professor 

 H. E. Jordan. 



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