TABLE OF CONTENTS. 



u 



CHAPTER II. 



PEVELOPMENT OF TIIE EMDr.YO FUOM TIIE TIME THE EGO LEAVES TIIE OVARY TO THAT OF 



THE HATCHING OF THE YOUNG. 



SivCTiox 1. Tlie lai/lny of the t'l/g"- — Jmportanco of local 

 infonnation respectinj; tlie Iiabits of animals. The in- 

 habitants of tlio country liave much knowledge upon 

 this subject that is not yet recorded. Period of lajing. 

 Passage of the eggs through the oviduct. Turtles lay 

 only once a year. p. 493-501. 



Section 2. Depusiliun of the alhumen and farmatUm "/the 

 shell. — The albumen and shell membrane, p. 501-507. 

 The shell, p. 508. 



Section 3. The uhsurption of allnimen into the yolk' sac. — 

 The alliun\en is gradually absorbed into the yolk sac, 

 p. 511-513. This also takes place in birds' eggs, p. 

 513. 



Section 4. The transformations of the yolk in the fecun- 

 dated egg. — Enlargement of the mesoblast, p. 51G. 

 Sudden multiplication of the entoblasts, p. 517. Seg- 

 mentation of the mesoblast, p. 517. It results in the 

 formation of the primitive cellular basis of the germ, 

 p. 522. 



Section 5. Segmentation of the yolk. — The segmentation 

 of the yolk takes place during the passage of the egg 

 tlirough the oviduct. The embryonic disc and the 

 germinal layer, p. 523-528. 



Section 6. The whole egg is the embryo. — There is no 

 natural limit between the development of the embryo, 

 from its first appearance as egg to the formation of a 

 distinct germ, and its ultimate growth. Continuity of 

 the genetic process, p. 528-534. 



Section 7. Foldings of the eml/ryouic dhc, and successive 



stages of ijrowth of the Turtle. — The embryonic disc, 

 p. 535. Tlie amnios, p. 53G. Growth of the embrjo, 

 p. 542-578. 



Section 8. Formation and development of the organs. — 

 The brain, p. 579. The chorda dorsalis, p. 584. The 

 eye, p. 584. The ear, p. 590. The nostrils, p. 591. 

 The vertebral column, p. 591. The skull, p. 592. 

 The shield, p. 592. The limbs, p. 593. The heart, p. 

 594. The bloodvessels, p. 597. The intestine, p. 600. 



Section 9. Ilistulogy. — The amnios, p. 602. The spinal 

 marrow, p. 602. The medulla oblongata, p. 602. The 

 hemispheres, p. 602. The olfactory lobes, p. 603. The 

 olfactory nerve, p. 603. The Schneiderian membrane, 

 p. 604. The pia mater, p. 604. The chorda dorsalis, 

 p. 604. The vertebra;, p. 605. The ribs, p. 606. The 

 limbs, p. 607. The skin, p. 608. The eye, p. 609. 

 The ear, p. 611. The intestine, p. 611. The allantois, 

 p. 613. The urinary bladder, p. 614. The lungs, p. 

 614. The trachea, p. 615. The liver, p. 615. The 

 gall cyst, p. 615. The bloodvessels, p. 615. The gen- 

 ital organs, p. 615. The kidneys, p. 615. The Wolf- 

 fian bodies, p. 616. The blood, p. 616. The muscles, 

 p. 617. The tendons, p. 618. 



Section 10. Chronology of the development of the embryo. 

 From the first segmentation of the yolk to the period 

 of hatching, we trace thirty-one stages of development, 

 p. 618-622. 



Explanation of the Plates, p. 623-640. 



Appendix and Euuata, p. 641. 



