XVI CONTENTS. 



PAGE 



Summary = . 489 



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

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

 (S) . „ ;= Membranous Ear-Capsule into 



the Bony Labyrinth and the 

 Perilymphatic Spaces . 498 



(c) ,1 „ „ Middle and External Ear . . 505 

 SUMMAEY 510 



C. The Development of the Organ of Smell , , . . 511 



Stjmmaby ... 518 



IIL The Development of the Skin and its Accessory Organs 520 



(a) The Skin . . 520 



(J) ,. Hair . . . ... 523 



(e) „ Nails . . . , ... 526 



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

 Summary . . . . . . . . 531 



CHAPTER XVII. 



THE ORGANS OP THE INTERMEDIATE LAYER OR MESENCHYME 538 



I. The Development of the Blood-vessel System . . . 542 



A. The first Developmental Conditions of the Vascular System . 642 



(a) Of the Heart ... 542 



(J) Vitelline Circulation, Allantoic and Placental Circulation 549 

 S. 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 



(J) 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 oe the Skeleton ..... 593 



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



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



(J) „ „ „ 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 



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



(a) Pectoral and Pelvic Girdles 638 



(J) Skeleton of the Free Extremity . . ... 640 



(c) Development of the Joints 644 



Summary 647 



APPENDIX TO LITERATURE , . . ^ 658 



