150 CAROTINOIDS AND RELATED PIGMENTS 



controlled chromatophores and the consequent power to change color 

 has been developed to a high point of perfection in the lizards. 



Among the snakes, which frequently are marked with yellow colors, 

 lipochromes in the broad sense and thus carotinoids, in the narrower 

 sense, do not appear to occur. Kiihne (1878) noticed the absence of 

 retinal pigments in snakes. According to Krukenberg (1882d) the 

 yellow pigment which can be extracted after long boiling with absolute 

 alcohol from the skin, muscles, connective tissue and fatty tissue of 

 the snakes, Tropidonotus natrix, Elaphis quadrilineatis Bonaparte, 

 Callopeltis quadrilineatis Pallas and Rhinescis scalaris, and which is 

 soluble is ether, CHC1 3 and CS 2 after extraction, differs from the 

 lipochromes in the persistent green fluorescence of its solutions, the 

 failure tc show absorption bands or chromatic reactions, and the 

 failure to bleach with oxidizing agents. Similarly, according to Cun- 

 ningham and MacMunn (1893) the yellow skin pigment of the alliga- 

 tor is not lipochrome. 



Among the lizards, however, the presence of ether and alcohol 

 soluble pigments of yellow color was apparently observed by a num- 

 ber of workers before Krukenberg (1882d, n) first submitted them 

 to spectroscopic examination. Using the skins of the cameleons 

 Lacerta muralis, Lacerta agilis, Camaelon vulgaris and Bombinator 

 igneus, the yellow and orange pigments were extracted and found to 

 correspond completely with other yellow and orange lipochromes. 

 The position of the two absorption bands resembled most those previ- 

 ously found by Krukenberg for the feather pigment zoofulvine, but 

 because of an uncertainty in his mind as to the identity of the pig- 

 ments, Krukenberg called the lizard pigment lacertofulvine. In all 

 probability the pigment is xanthophyll, or at least one of this group of 

 carotinoids. 



Among turtles we have the observation of Halliburton (1886) that 

 the blood serum and adipose tissue of the tortoise is rich in a lipo- 

 chrome showing the spectroscopic and other lipochromatic characters 

 of the blood serum and adipose tissue pigments of the hen. The ques- 

 tion needs further study, however, before it can be even regarded as 

 probable that this pigment is xanthophyll. 



Summary 



Piccolo and Lieben (1866) and Holm (1867) isolated the first ani- 

 mal chromolipoid in pure condition, namely, the pigment of the corpus 



