XVI CONTENTS. 



PAGE 



SUMMARY . 489 



B. The Development of the Organ of Hearing .... 490 



(a) The Development of the Otocyst into the Labyrinth . 491 

 (&) ., Membranous Ear-Capsule into 



the Bony Labyrinth and the 

 Perilymphatic Spaces . 498 



(c) M Middle and External Ear . . 505 

 SUMMARY 510 



C. The Development of the Organ of Smell 511 



SUMMARY ^ . . 518 



III. THE DEVELOPMENT OF THE SKIN AND ITS ACCESSORY ORGANS 520 



(a) The Skin ' . . . .520 



(5) ,. Hair 522 



O) Nails .526 



(d) Glands of the Skin . . . ... , .528 



SUMMARY . 531 



CHAPTER XVII. 

 THE ORGANS OF THE INTERMEDIATE LAYER OR MESENCHYME 538 



I. THE DEVELOPMENT OF THE BLOOD-VESSEL SYSTEM . . . 542 



A. The first Developmental Conditions of the Vascular System. . 542 



(a) Of the Heart ... 542 



(&) Vitelline Circulation, Allantoic and Placental Circulation 548 



B. The further Development of the Vascular System up to the 



Mature Condition 553 



(a) The Metamorphosis of the Tubular Heart into a Heart 



with Chambers . . 553 



(&) The Development of the Pericardial Sac and the Dia- 

 phragm , -. . . 566 



(c) Metamorphoses of the Arterial System . 570 



(d) ,, ., Venous .-. .... 577 

 SUMMARY . 588 



II. THE DEVELOPMENT OF THE SKELETON 593 



A. The Development of the Axial Skeleton . . , . ' . 593 



(a) The Development of the Vertebral Column . . . 596 



(&) Head -Skeleton . . . .603 



I. Bones of the Cranial Capsule . . . . . 619 



II. Visceral Skeleton . . . .' .622 



(c) Concerning the Relation of the Head-Skeleton to the 



Trunk-Skeleton 627 



E. The Development of the Skeleton of the Extremities . . 635 



(a) Pectoral and Pelvic Girdles 638 



(&) Skeleton of the Free Extremity . , . . .640 

 (c) Development of the Joints ...... 644 



fiUMMABY 4 .... 647 



APPENDIX TO LITERATURE . . 658 



