CONTENTS OF VOLUME XIII. 



No. 1. — Miocene Land Shells from Oregon. Plate I. By G. Dallas Hanna. 



No. 2. — Plei-stocene Mollusks from Wallace County. Kansas. By G. Dallas 

 Hanna. 



No. 3. — Moisture Requirements of Germinating Seeds. By Rupert Peters. 



No. 4. — A Special Riemann Surface. Plates II to V. J^y H. H. Conwvll. 



No. 5. — A Calculation of the Invariants and Covariants for Ruled Surfaces. 

 By E. B. Stouffer. 



No. 6. — Possible Methods of Classifying White, Yellow and Orange Staphy- 

 lococci. By Martha Bays. 



No. 7. — Anguillavus hackberryensis. Plate VI. By H. T. Martin. 



No. 8. — Continuation of Investigation of a Possible Rainfall Period Equal to 

 One-ninth the Sun-spot Period. By Dinsmore Alter. 



No. 9. — Application of Marvin's Periodocrite to Rainfall Periodicity. By 

 Dinsmore Alter. 



No. 10. — On the Preparation of the Aryl Isothiocyanates. By F. B. Dains, 

 R. Q. Brewster, C. P. Olander. 



No. 11. — A Rainfall Period Equal to One-ninth of the Sun-spot Period. By 

 Dhhwiore Alter. 



No. 12. — Indications of a Giant Amphibian in the Coal Measures of Kansas. 

 Plate I to III. By H. T. Martin. 



No. 13. — On Some Isothionrea Ethers. By F. B. Dains and W. C. Thompson. 



No. 14. — The Size of the Thj-mus Gland in Relation to the Size and Develop- 

 ment of the Foetal Pig as Studies in a Varied Range of Stages. By 

 Donald N. Medearis and Alexander Marble. 



No. 15. — A Comparison of the Antigenic and Cultural Characteristics of a 

 Number of Strains of Bacillus typhosus. By Cora M . Downs. 



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