CONTENTS. 



PAGE 



Officers and Committees for 1893 . . . . iv 



Joint Commission for 1893 ..... iv 



Proceedings ........ v-xiii 



Addresses and Communications : 



A Jumping Mouse (Zapus insignis Miller) new to the United 

 States. By Gerrit S. Miller, Jr., 1 



Paleontology of the Cretaceous Formations of Texas. The In- 

 vertebrate Paleontology of the Trinity Division. By Robert 

 T. Hill, 9 



Further notes on Yucca Insects and Yucca Pollination. By 

 C. V. Riley, 41 



Description of a new White-footed Mouse from the Eastern 



United States. By Gerrit S. Miller, Jr .55 



Development of the Brachial Supports in Dielasma and Zygos- 

 pira. By Charles E. Beecher and Charles Schuchert. And on 

 the Development of the Shell ot Zygospira recurvirostra. By 

 Charles Schuchert, 71 



Re-discovery of the Mexican Kangaroo Rat, Dipodomys Phil- 

 lipsi Gray. By C. Hart Merriam, M. D. With field notes by 

 E. W. Nelson, 83 



The Paleontology of the Cretaceous Formations of Texas. The 

 Invertebrate Fossils of the Caprina Limestone Beds. By 

 Robert T. Hill, 97 



Two new Wool- rats from the plateau region of Arizona (Neo- 

 toma pinctorum and N. Arizonse), with remarks on the 

 Validity of Genus Teonoma of Gray. By C. Hart Merriam, 

 M.D., 109 



Notes on Thomomys bulbivorus. By Gerrit S. Miller, Jr., . . 113 



Description of a new Species of Lagomys from Alaska. By E. 

 W. Nelson, . 117 



Juncus marginatus and its Varieties. By Frederick Vernon 

 Coville, 121 



Description of eight new Ground Squirrels of the genera Sper- 

 mophilus and Tanrias from California, Texas and Mexico. 

 By C. Hart Merriam, M. D., 129 



Description of a new Species of Arvicola of the Mynomes 

 group from Alaska. By E. W. Nelson, 139 



Preliminary Descriptions of four new Mammals from Southern 

 Mexico, collected by E.W. Nelson. By C.Hart Merriam, M.D., . 143 



The Yellow Bear of Louisiana, Ursus luteolus Griffith. By C. 



Hart Merriam, M. D., 147 



Index, 153 



