[119] EMBRYOGRAPHY OF OSSEOUS FISHES. 573 



TABLE OF CONTENTS. 



Page. 



1. Introductory 1 



2. The ova and ovaries of the cod and other fishes 3 



3. The fate of the germinative vesicle 13 



4. Development of the germinal disk 16 



5. Impregnation of the egg ■. 19 



6. Origin of the yelk hypoblast 28 



7. Segmentation of the germinal disk 31 



8. Transformation of the germinal disk into the blastoderm 36 



9. The development of the germinal layers 40 



10. Development of the cerebro-spinal axis or neurula 41 



11. The development of the brain 49 



12. The olfactory and auditory organs 52 



13. The lateral sensory organs of the larval cod 54 



14. Development of the notochord 56 



15. Development of the ribs 60 



1(). Development of the skull 61 



17. Development of the unpaired or median fins 62 



18. The development of the paired fins 65 



It). Development of the lateral muscle-plates and somites 68 



20. Development of the intestine and its appendages 72 



21. Development of the renal organs or corpora Wolffiana 79 



22. Development of the heart 82 



23. Development of the circulation and function of the yelk hypoblast 86 



24. Development of the pigment cells of young fishes 93 



'^5. The law of displacement of the germinative vesicle 95 



26. On some of the phenomena of segmentation and growth 101 



27. The gastrula and cceloma of Teleosts 108 



28. The development of the eggs of the codfish 115 



