CONTENTS XXV 



IX. The Metabolism and Nutritional Value of the Carotenoids and 

 Vitamins A (^continued) 



(a) The Effect of Diet 470 



a'. Vitamin A Tolerance Curves 471 



(b) Physiologic Factors Altering Blood Vitamin A 472 



(c) Pathologic Factors Altering Blood Vitamin A 474 



G. The Storage of Carotenoids and of Vitamins A 475 



( 1 ) Comparative Distribution in Different Animals 476 



a. In Invertebrates 476 



(a) Carotenoids in Protozoa 476 



(b) Carotenoids in Metazoa 477 



a'. Porifera (Sponges) 477 



b'. Cnidaria 477 



(c) Carotenoids in Echinodermata 479 



a'. Asteroidea 479 



b'. Ophiuroidea 480 



c'. Holothuroidea 480 



d'. Crinoidea 480 



e'. Echinoidea 480 



(d) Carotenoids and Vitamins A in Arthropoda 481 



a'. Crustacea 481 



a". Possible Sources of Vitamin A for the Whale 485 



b'. Mollusca 486 



a". Lamellibranchiata 486 



b". Cephalopoda 487 



c". Gastropoda 487 



c'. Insecta 488 



a". Coleoptera 488 



b". Lepidoptera 488 



c". Hemiptera 489 



d". Hymenoptera 490 



e". Orthoplera 490 



f". Resume of the Occurrence and Function of Carot- 

 enoids in Insecta 494 



b. In Vertebrates 495 



(a) Carotenoids and Vitamins A in Fishes 495 



(b) Carotenoids and Vitamins A in Aquatic Mammals 499 



(c) Carotenoids and Vitamins A in Amphibia 500 



(d) Carotenoids and Vitamins A in Reptiles 502 



(e) Carotenoids and Vitamins A in Birds (Aves) 503 



(f) Carotenoids and Vitamins A in Higher Vertebrates 509 



a'. Man 510 



b'. Cattle 512 



c'. Horses 514 



d'. Sheep 514 



e'. Miscellaneous Animals Which Do Not Accumulate 



Carotenoids 514 



