UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



ZOOLOGY 



Vol. 13, No. 12, pp. 447-494, pi. 38-39, 20 text figs. March 7, 1916 



ANATOMICAL ADAPTATIONS IN THE 



THORACIC LIMB OF THE CALIFORNIA POCKET 



GOPHER AND OTHER RODENTS 



BY -/v-jn Iftfi 



CHARLES DANIEL HOLLIGER 



CONTENTS ^'^'^"'^^aLJ^ 



PAGE 



Introduction 447 



Correlation of Anatomy with Habits 448 



Selection of Material 448 



Habits of the Rodents Studied 449 



Plan of the Work 450 



Osteology 451 



Myology 462 



Grouping of Muscles According to Function 481 



Volumetric Measurements 483 



Deductions from Volumetric Figures 485 



Summary 489 



Bibliography 490 



INTRODUCTION 



Structural adaptations are interesting, not only because of their 

 close connection with problems of heredity and speciation, but also 

 because they are the basis of the interest which inherently attaches 

 to specialized forms. When we see a highly modified animal type 

 we naturally look about to see what factors in the animal's environ- 

 ment have been responsible for the specialized developments in its 

 morphology. Every such study of modified forms must necessarily 

 be accompanied by comparison, since specialization is always a rela- 

 tive term. 



It was with the idea of studying anatomical adaptation to habits 



