

CONTENTS OF A^OLUME XXVI 



Page 



Title page ,. i 



Officers ii 



Contents ill 



Dates, of publication and editions of the brochures iii 



List of illustrations iv 



Geological Reconnoissance of Porto Rico. By Charles P. Berkey. 



(Plates I-III) 1 



List of Greater Antillean Spiders, with Notes on Their Distribution. 



By Frank E. Lutz 71 



Volcanic Dust Veils and Climatic Variations. By Henryk Arctowski. .. 149 

 Statistical Study of Variation in Spirifer mucronatus. By Charles C. 



MooK 175 



Review of the Pleistocene of Europe, Asia and Northern Africa. By 



Henry Fairfield Osborn .' 215 



Present Status of the Problem of the Origin of the Tetrapoda. By Wil- 

 liam K. Gregory. (Plate IV) 317 



Biochemical Studies of Selenium. By Victor E. Levine. (Plate V) 385 



Records of Meetings, 1915. By Henry E. Crampton 395 



Membership Lists, 31 December, 1915 463 



Index 475 



DATES OF PUBLICATION AND EDITIONS OF THE BROCHURES 



Pp. 1-70, 3 March, 1915 

 Pp. 71-148, 29 May, 1915 

 Pp. 149-174, 21 June, 1915 

 Pp. 175-214, 30 June, 1915 

 Pp. 215-315, 30 July, 1915 

 Pp. 317-383, 7 July, 1915 

 Pp. 385-394, 18 October, 1915 

 Pp. 395-486, 12 May, 1916 



Edition 

 1450 copies 

 1075 copies 

 1200 copies 

 1150 copies 

 1350 copies 

 1250 copies 

 1310 copies 

 1000 copies 



111 



