TABLE OF CONTENTS. 



1. Introduction 1. 



2. Species used 3. 



3. Anatomical details on the digestive tract 4. 



4. Biology. Prey 10. 



5. Toxicity of the starfish stomach. . 14. 



6. The enzymes, a. proteolytic ... . . 18. 



b. sucrolytic 21. 



c. lipolytic .22. 



7. Are the enzymes free? Phagocytosis in Echinoderms . . 22. 



8. Autolysis in Echinoderm guts 26. 



9. Contents of the gut of Thyone .... ... 27. 



10. Composition of the faeces of Arbacia. 28. 



11. Ph of the gut contents 30. 



12. The digestive fluid .... . . . . 34. 



13. Transportation of the food. The perivisceral fluid ... 37. 



14. Are there enzymes in the perivisceral fluid?. ... .41. 



15. Role of the corpuscles 42, 



16. The digestion and utilisation of fatty substances. Emulsifying 



enzymes ? 43. 



17. Lactic acid development in autolysates of the liver . . . 50. 



18. Lipolytic enzyme in the amibocytes of the Asteroidea? . . 52. 



19. The nitrogen metabolism of the Holothurians 54. 



20. The resorption in Echinoidea and Hblothuroidea . . .56. 



21. The resorption in Asteroidea. Function of their „liver". . 65. 



22. The resorption from the perivisceral fluid 74. 



23. Excretion in Echinoderms. Function of the rectal coeca 



of the Asteroidea 80. 



24. Respiration, a. General 88. 



b. Are there catalases and peroxydases in the 

 perivisceral fluid? 90. 



c. Contents of the Polian vesicles of Thyone. 

 Importance of the water vascular system 



in respiration 92. 



25. Reserve substances in Echinoderms. . . 95. 



26. General metabolism . 97. 



27. Bibliography 104. 



