XVI CONTENTS. 



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 . 49* 



(tf) Middle and External Ear . . 505 



SUMMARY ............ 510 



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

 SUMMARY .......... . 518 



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

 O) The Skin .......... 520 



(1>) 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 



O) Of the Heart ......... 542 



(&) Vitelline Circulation, Allantoic and Placental Circulation 549 



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 ........ 533 



(V) The Development of the Pericardia! Sac and the Dia- 



phragm ......... 566 



(p) Metamorphoses of the Arterial System .... 570 



(d) Venous .... 577 



SUMMARY ............ 588 



II. THE DEVELOPMENT OF THE SKELETON ..... 593 



-4. 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 



Concerning the Relation of the Head-Skeleton to the 



Trunk-Skeleton ........ 627 



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

 (a) Pectoral and Pelvic Girdles ...... 638 



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



(c 1 ) Development of the Joints ...... 644 



SUMMARY ............ 647 



APPENDIX TO LITERATURE . . 658 



