CONTENTS. 



CHAPTER XV. 

 THE ORGANS OF THE MIDDLE GEEM-LAYEB 



I. The Development of the Voluntaey Musculature 

 A. The Primitive Segments of the Trunk ... 



PAGE 



. 341 

 . 342 

 . 342 



-B. „ Head-Segments 351 



II. The Development of the Ueinaey and Sexual Organs . 353 

 (a) The Pronephros and the Mesonephric Duct .... 358 



(&) „ Mesonephros (Wolffian Body) 359 



(c) „ Metanephros (Kidney) . , . , . . 367 



{d) „ Mlilleriau Duct 369 



(e) „ Germinal Epithelium . . 374 



(/) „ Ovary 374 



(jf) „ Testis 382 



(/() „ Metamorphosis of the DifEerent Fundaments of the Uro- 

 genital System into their Adult Condition . 385 

 A. In the Male {Deseensm tegtieulorum) . . . 387 



.393 



. .■!97 



403 



. 405 



B. „ „ Female ( „ ovariorma) 

 (i) The Development of the External Sexual Parts 

 III. The Development of the Suprarenal Bodies 

 Summary ... 



CHAPTER XVI. 

 THE OEGANS OF THE OUTER GERM-LAYER 416 



The Development of the Nervous System . 

 A. The Development of the Central Nervous System 

 (a) The Development of the Spinal Cord 

 (fi) „ „ „ Brain . 



(1) Metamorphosis of the fifth Brain-Vesicle 



(2) 

 (3) 

 (4) 



(5) 



416 

 416 

 418 

 421 



427 

 429 

 430 

 431 



„ „ fourth „ „ 



„ „ third ., „ 



„ „ second „ „ 



Development of the Pineal Gland (Epiphysis cerebri) 432 



„ „ Hypophysis (Pituitary Body) . 436 



„ „ Fore-Brain Vesicle . . .439 



S. The Development of the Peripheral Nervous System 

 (a) „ „ Spinal Ganglia . 

 (J) „ „ Peripheral Nerves 

 (c) „ „ Sympathetic System 

 Summary 



II. The Development of the Sensory Oruans 

 A. The Development of the Eye 



(a) The Development of the Lens . 



(*) „ „ „ Vitreous Body 



(c) „ „ ,, Secondary Optic Cup and the 



Coats of the Eye 



(d) „ „ „ Optic Nerve 



449 

 449 

 452 

 462 

 463 

 467 

 467 

 471 

 474 



476 



484 



(«) 



Accessory Apparatus of the Eye 486 



