CONTENTS.

 Page.
Introduction[17]
 Development of Vertebrate Ovum[19]
 Development of Cœlom and of Alimentary Canal[21]
 Development of Cloaca[24]
 Development and Divisions of the Peritoneum[32]
 Derivatives of Entodermal Intestinal Canal[34]
 Divisions of Alimentary Canal[38]
Part I. Anatomy of the Peritoneum and Abdominal Cavity[39]
 Comparative Anatomy of Foregut and Stomach[42]
 Morphological Types of Stomach[43]
 Development of the Intestine[51]
  I.Intestinal Rotation and Definition of Adult Segments of the Intestinal Canal[58]
   Development of Aortal Arterial System[63]
  II.Demonstration of Intestinal Rotation in the Lower Mammalia[67]
   Peritoneal and Visceral Relations in the Infra-colic Compartment of the Abdominal Cavity in the Adult[74]
Part II. Anatomy of the Peritoneum in the Supra-colic Compartment of the Abdomen[99]
 1.Stomach and Dorsal Mesogastrium[100]
  a.Changes in Position of Stomach[102]
  b.Changes in Direction and Extent of Dorsal Mesogastrium[103]
  c.Development of Spleen and Pancreas in the Dorsal Mesogastrium and Changes in the Disposition of the Great Omentum[108]
   1.Development of Spleen[108]
   2.Development of Pancreas[111]
    Development of Pancreas in Lower Vertebrates[115]
    Comparative Anatomy of Pancreas[116]
    Pyloric Cæca or Appendices[119]
    Peritoneal Relations of Pancreas[122]
    Comparison of Embryonal Stages during the Development of the Human Dorsal Mesogastrium, Spleen and Pancreas with the Permanent Adult Condition of the same Structures in Lower Mammalia[126]
   1.Spleen, Pancreas and Great Omentum of Cat[127]
   2.Relation of Great Omentum to Transverse Colon, Transverse Mesocolon and Third Part of Duodenum[129]
 2.Ventral Mesogastrium and Liver[140]
  I.A.Development of Liver[141]
   B.Comparative Anatomy of Liver[144]
   C.Development of Vascular System of Liver[145]
    Comparative Anatomy of the Hepatic Venous Circulation[154]
  II.Ventral Mesogastrium[163]
   Peritoneal Relations of Liver[167]
   Relation of Hepatic Peritoneum to the “Lesser Sac”[174]
   Caudal Boundary of Foramen of Winslow[178]
   Pancreatico-gastric Folds[181]
Part III. Large and Small Intestine, Ileo-colic Junction and Cæcum[189]
 I.General Review of Morphology and Physiology of the Vertebrate Intestine[190]
  I.Midgut or Small Intestine[192]
   Intestinal Folds[193]
   Divisions of Small Intestine[194]
   Structure of Small Intestine[194]
   1.Secretory Apparatus[194]
   2.Absorbing Apparatus[195]
   Valvulæ Conniventes[196]
  II.Endgut or Large Intestine[198]
 II.Serial Review of the Ileo-colic Junction and Connected Structures in Vertebrates[200]
  I.Fishes[200]
  II.Amphibia[201]
  III. Reptilia[201]
  IV.Birds[203]
  V.Mammalia[204]
    Monotremata[204]
    Marsupalia[204]
    Edentata[206]
    Sirenia[208]
    Cetacea[209]
    Ungulata[209]
    Rodentia[211]
    Carnivora[212]
    Cheiroptera[212]
    Insectivora[213]
    Primates[213]
 III. Phylogeny of the Types of Ileo-colic Junction and Cæcum in the Vertebrate Series[217]
  1.Symmetrical Form of Ileo-colic Junction; Mid- and End-gut in Direct Linear Continuity[221]
  2.Asymmetrical Development of a Single Cæcal Pouch, lateral to the Ileo-colic Junction, Mid- and End-gut Preserving their Linear Continuity[223]
  3.Rectangular Ileo-colic Junction, with Direct Linear Continuity of Cæcum and Colon[225]
 IV.Structure of Cæcal Apparatus and Specialized Morphological Characters of Colon in Rodents and Ungulates[229]
  1.Cæcum Proper[229]
  2.Structural Modifications of Proximal Segment of Colon analogous in their Functional Significance to the Cæcal Apparatus[230]
 V.Cæcal Apparatus and Colon in Hyrax.[234]
Part IV. Morphology of the Human Cæcum and Vermiform Appendix[237]
 I.Development of the Cæcum and Appendix[237]
 II.Changes in the Position of the Cæcum and Appendix during normal Development, depending upon the Rotation of the Intestine and the subsequent Descent of the Cæcum[239]
 III.Variations of Adult Cæcum and Appendix[244]
  A.Shape of Cæcum and Origin of Appendix. Types and Variations of Adult Cæcum and Appendix[245]
  B.Position and Peritoneal Relations of Appendix[250]
  C.Ileo-Cæcal Folds and Fossæ[260]

INTRODUCTION.

In considering the anatomy of the human abdominal cavity and peritoneum in the following pages the explanation of the adult conditions encountered is based upon the development of the parts, and the successive human embryonal stages are illustrated by the examination of the lower vertebrates presenting permanent adult structural conditions which appear as merely temporary embryonal stages in the development of the higher mammalian alimentary tract.

For the sake of clearness and brevity all discussion of the theories of peritoneal development has been designedly omitted. The assumption of peritoneal adhesion, and consequent obliteration of serous areas, offers many advantages in considering the adult human abdominal cavity, especially from the standpoint of comparative anatomy. The same has consequently been adopted without reference to divergent views and theories.

In studying the descriptive text and the diagrams the student should remember that the volume offers in no sense a complete or detailed account of the development of the abdominal cavity and its contents. The purpose is not to present the embryology of this portion of the vertebrate body, but to utilize certain embryological facts in order to explain the complicated adult conditions encountered. To avoid confusion, and to bring the salient points into strong relief, the majority of the diagrams illustrating human embryonal stages are purely schematic.