The American Naturalist 



A Monthly Journal, establuhed in 1867, Devoted to the Advancement of the Biological Science, 

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



OONTENT8 OF THE APRIL NUMBER 



The fessor Chvrles 3 ^^* 116 Species Q uestion - *«>- 

 The Taionomic Aspect of the Species Question. Dr. 

 The^Physiolo^ic^spect^of the Species Question. Pro. 

 The^Physiological Aspect of a Species. Dr. D. T. 

 An Ecologic View of the Species Conception. Professor 

 An Ecological Aspect of the Conception of Species. Dr. 



OONTENT8 OF THE MAY NUMBER 



^^aU^P^^3»^U^MB^&^ i ^ ^elugher 



OONTENT8 OF THE JUNE NUMBER 



The Ancestry of the Caudate Amphibia. Dr. Rot L. 



The Spirochetes and their Relationship to other Organ- 



The Faunal Affinities of the Prairie Region of Central 



North America. Dr. Alexander O. Bcthven. 

 Physiology. Professor Frederic S. Lee. 



to Theory, Professor Raymond Pearl. Protozoa— 



A New Mendelian Ratio and Several Types of Latency. 



Notefand^LiSra^ ? f *J* 

 Eel, Professor Char ursATkororo; The Valw h» 



Pl'ant'Cets, D^BrXeT tf.^AVTa?* 8 ™ 



CONTENTS OF THE AUGUST NUMBER 



^sfud^TofesSrt. A^LS? " ! A Statistical 



P^bdgaPediculata n. sp. Erstest E. Heminway 



a °^r Art^l^^d^CtorreiipondBnM : The Genus Ptilo- 

 James Cook. ^ " 10Cene ° f Nebnt8ka » Harold 



CONTENT8 OF SEPTEMBER NUMBER 



Some results of the Florissant Expedition of 190»- 



Another Aspect of the Species Question. Db. J A. 

 The^ Origin of ^the^ Lateral Eyes of Vertebrates 



logical Studies on D ^ ol %^°riS H^* 1 



WiLLisToS* JtawUMft^Tfce Evolution of 



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The NATURALIST will be Mat to new subscriber* for four months for One Doll*' 



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