AUTHOR’S ABSTRACT OF THIS PAPER ISSUED 
BY THE BIBLIOGRAPHIC SERVICE, FEBRUARY 24 
A STUDY OF THE CORRELATION OF THE PELVIC 
STRUCTURE AND THE HABITS OF CERTAIN 
BURROWING MAMMALS 
ROYAL NORTON CHAPMAN 
From the Zoological Laboratory, Cornell University 
FIVE PLATES (TWENTY-SIX FIGURES) 
CONTENTS 
Teg NRCG ITA isa ee a EE: be Aa 2 MRS eS en Re 185 
MRE STEUCEHTE OL thesPel Vises. seamen ioe + «cele eee se Beles Aargele SS ws 187 
i; Lhe pelvie bones: of the Rodentia..25 25... ccus cine st ose site nes = 2 187 
Zeeinespelvicsbomes-or theudnsectiwvGnan.. 7.25. 2658s. ceca. eee es 192 
3. The pelvic bones of the marsupial mole (Notoryctes)..........--+++++- 194 
4. A classification of the pelves of burrowing mammals..............-+-- 194 
Therstatus of the rectus, abdominis muscles: ........--+-.+s +2227 s 005s se ss = 195 
1. The relations of the rectus abdominis muscles of the Rodentia........ 196 
2. The relations of the rectus abdominis muscles of the Insectivora...... 197 
The relation of the pelvic estates and the habits.................-+--+2055 198 
it Bhe attainment of the horizontal pelvis: 2.2.6. .56.-.0<2 082s ese ees oe 198 
Pehiculoss, OF he Symp MySis: PUDIS: a sete. - gas siesew sss aje aoe mes ee oles 199 
3. The persistence of the symphysis in certain caseS............+-+++++++ 203 
4. The function of crossed rectus abdominis muscles..............++++++5 205 
SHTECTECT 15 GSS NN ee SEP RI et Str Wor Eke Aa A RE a a Sr a 206 
INTRODUCTION 
The results embodied in this paper are from data accumulated 
during several years of observation. This line of work first 
suggested itself during the examination of specimens in the 
field. It was noticed that the pocket gophers (Geomys bur- 
sarius) have two types of pelvis, one with a symphysis and the 
other without. This led to a more extended investigation of 
the pelvis of burrowing mammals, resulting in the revelation 
that they possess certain structural characteristics In common. 
Huxley (’75), in a consideration of the mammalian pelvis, 
employed certain angles to show the progress of its phylogenetic 
development. A longitudinal line drawn through the centra of 
185 
