ANIMAL CHLOROPHYLL 367 



son, 1920). This, however, does not in any way destroy the 

 value of their work, which is a most fundamental contribution 

 to our knowledge of the crystal structure of proteins. 



Chlorocruorin. — This pigment, though green in colour, 

 is closely allied to haemoglobin. The substance was noted by 

 Milne-Edwards (1838), but was first isolated by Lankester 

 (1869) from Sabella ventrilabrum and Siphonostoma. 

 MacMunn (1883 a) subsequently identified it in Serpula 

 contortuplicata.^ Though the absorption bands of 

 chlorocruorin present a striking similarity to that of haemo- 

 globin, the green pigment cannot be broken down into any of 

 the decomposition products of the red pigment. Chlorocruorin, 

 however, is definitely respiratory and is capable of existing in 

 two states of oxidation, oxychlorocruorin and reduced chloro- 

 cruorin. The pigment is found both in the blood and in the 

 epidermis, and the animals possessing chlorocruorin owe their 

 colour almost entirely to its presence. 



Chlorophyll. — The only authentic example of a chloro- 

 phyllous pigment existing in annelids is that of Bonellia 

 viridis. Sorby (1875 6) showed that this pigment gave 

 absorption bands which were practically identical with chloro- 

 phyll, but Geddes (1882) failed to find any evolution of oxygen 

 in the tissues of Bonellia when it was exposed to strong sun- 

 light. Krukenberg likewise obtained negative results (Geddes). 

 However this may be, it is most probable that bonellein is 

 a derivative of chlorophyll, particularly in view of the recent 

 investigations of Hans Przibram (1913), which have demon- 

 strated striking spectroscopic similarities between the two 

 pigments. 



Lipochromes . — The blood of A r e n i c o 1 a p i s c a t o r u m 

 has, in addition to haemoglobin, certain lipochromes, some of 

 which give absorption bands (MacMunn, 1883 a, 1889). Mac- 

 Munn, in addition, found that a lipochrome present in the 

 digestive tract was found also in the epidermis. Fauvel (1899) 



^ It is a curious fact that the pigment of Serpula, though spectroscopi- 

 cally identical with that of Sabella, is red in colour. Griffiths (1897) 

 believes that the two pigments are isomeric. 



