CAROTINOIDS IN THE VERTEBRATES 153 



pigment of the flesh and ovaries appears to be the carotinoid-like 

 rarotinin described above. 



Among amphibians the yellow pigments of the skin, adipose tissue 

 and retina of frogs, toads and salamanders are unquestionably caro- 

 tinoids, but the evidence at hand does not show whether carotin or 

 xanthophyll or both are concerned. 



Yellow pigments among reptiles appear to be more frequently non- 

 carotinoid in nature. There is a probability, however, that a xantho- 

 phyll is the chromolipoid of camelcon skins. The blood serum and 

 adipose tissue of the tortoise also contain carotinoids, the nature of 

 which is not known. 



