The Variability of Zygospores in Spirogyra quadrafa 

 (Hass.) Formed by Scalariform and by Lateral 

 Conjugation, and Its Bearing on the Theory of 

 Amphimixis 68 



Symhiotes duryi, a New Species of Endomychidae 70 



Amphimixis, Variability and Death; Some Facts and a 

 Theory 73 



The Land Planarians of North America, with a Note 

 on a New Species 75 



Studies on the Mouth-Parts of Khyparobia maderw 

 (Blattidae) with a Consideration of the Homolo- 

 gies Existing between the Appendages of the Hex- 

 apoda 76 



The Evolutionary Control of Organisms and Its Sig- 

 nificance 78 



Cell Division and the Formation of Paramylon in Eu- 

 glena oxyuris Schmarda 93 



A Land Planarian with an Abnormal Number of Eyes 96 



Variability and Amphimixis 98 



Gametogenesis in Plans 126 



The Axial Rotation of Aquatic Microorganisms and Its 



Significance 130 



Eutetramorus glohosus, a New Genus and Species of 

 Algas Belonging to the Protococcoidea (Family) 

 Ccelastridas ) 132 



Organic Evolution and the Significance of Some New 

 Evidence Bearing on the Problem 13 5 



The Polychaete Ancestry of the Insects: I. The Ex- 

 ternal Structure 1 57 



Stenotarsiis blatchleyi, a New Endomychid from Flor- 

 ida (Coleoptera) 174 



The Word Caribou 177 



Determining the Average Fiber Length in Wool 



Yarns 179 



