1. Fig. 19.1. Spleen.

2. Fig. 19.2. Conducting system of mammalian heart.

3. Fig. 19.3. Structure of blood vessels.

5. Fig. 19.4. Aspects of the development of vertebrate circulatory systems.

6. Fig. 19.5. Development of hepatic portal system of mammals.

7. Fig. 19.6. Sagittal section through heart of Squalus.

8. Fig. 19.7. Blood vessels of an elasmobranch.

9. Fig. 19.7. Gill arches of an elasmobranch.

10. Fig. 19.8. Hemal arch of a teleost.

11. Fig. 19.9. Aortic arches and circ- ulation of African lungfish.

12. Fig. 19.10. Aortic arches of lissamphibians.

13. Fig. 19.11. Ventral dissection of a frog heart

14. Fig. 19.12. Heart and aortic arches of a turtle or “lizard”

15. Fig. 19.13. Turtle and crocodilian hearts compared.

16. Fig. 19.14. Aortic arches of birds and mammals compared.

17. Fig. 19.15. Development of human aortic arches.

18. Fig. 19.16. Changes in mammalian circulation at birth.

19. Focus 19.1. Evolution of gill arch circulation and aortic arches.

20. Fig. 19.17. Comparative anatomy of the venous system in the trunk.

21. Fig. 19.18. Development of the vena cava of Mammals.

22. Fig. 19.19. Internal and external jugular veins evolved from Anterior cardinal and inferior jugular veins.

23. Fig. 19.20. Lymphatic system.

24. Fig. 19.21. Lymph node.