1893.] on Turacin, a remarkable Animal Pigment. 47 



the south, 2 in the south-east, 4 in the east, 2 in the central, and 2 in 

 the north-east. It is noteworthy that, in all these sub-regions save the 

 south-east, turacin-bearers are found along with those plantain-eaters 

 which do not contain the pigmeut. Oddly enough two of the latter 

 species, Schizorhis africana and S. zonura, possess white patches 

 destitute of pigment in those parts of the feathers which in the 

 turacin-bearers are crimson. These birds do not, I will not say 

 cannot, decorate these bare patches with this curiously complex 

 pigment. [Some extracts were here given from the late Mr. 

 Monteiro's book on Angola, vol. ii. pp. 74-79, and from letters by 

 Dr. B. Hinde. These extracts contained references to curious traits 

 of the touracos.] 



Usually from 12 to 18 of the primaries or metacarpo-digitals 

 and secondaries or cubitals amongst the wing feathers of the turacin- 

 bearers have the crimson patches in their web. Occasionally the 

 crimson patches are limited to six or seven of the eleven primaries. 

 I have observed this particularly with the violet plantain-eater 

 (Musophaga violacea). In these cases the crimson head-feathers, 

 which also owe their colour to turacin, are few in number, as if the 

 bird, otherwise healthy, had been unable to manufacture a sufficiency 

 of the pigment. I may here add that the red tips of the crest 

 feathers of Turacus meriani also contain turacin. 



In all the birds in which turacin occurs, this pigment is strictly 

 confined to the red parts of the web, and is there unaccompanied by 

 any other colouring matter. It is therefore found that if a single 

 barb from a feather be analysed its black base and its black termina- 

 tion possess no coj^per, while the intermediate portion gives the blue- 

 green flash of copper when incinerated in the Buusen flame. [A 

 parti-coloured feather was burnt in the Bunsen flame, with the 

 result indicated.] 



Where it occurs, turacin is homogeneously distributed in the 

 barbs, barbicels and crochets of the web, and is not found in granules 

 or corpuscles. 



To the natural question " Does turacin occur in any other birds 

 besides the touracos ? " a negative answer must at preseut be given. 

 At least my search for this pigment in scores of birds more or less 

 nearly related to the Musophagidaa has met with no success. In 

 some of the plantain-eaters (species of Turacus and Gallirex) there 

 is, however, a second pigment closely related to turacin. It is of 

 a dull grass-green colour, and was named Turacoverdin by Dr. 

 Krukenberg in 1881. I had obtained this pigment in 1868 by 

 boiling turacin with a solution of caustic soda, and had figured its 

 characteristic absorption band in my first paper (Phil. Trans., 

 vol. clix. 1870, p. 630, fig. 4). My product was, however, mixed 

 with unaltered turacin. But Dr. Krukenberg obtained what 

 certainly seems to be the same pigment from the green feathers of 

 Turacus corythaix, by treating them with a 2 per cent, solution of 

 caustic soda. I find, however, that a solution of this strength 



