THEIR REPRODUCTION (EGGS) 283 



Lichenoxanthine, and lastly, an as yet unnamed 

 substance yielding narrow absorption-bands in 

 the red. These colours appear to be closely asso- 

 ciated with bile-pigments, although not actually 

 agreeing with them. Oorhodeine is present in 

 most eggs, its absence being exceptional, and 

 is brownish-red in colour ; Oocyan and Banded 

 Oocyan are, as their names suggest, blue ; 

 Yellow Ooxanthine and Rufous Ooxanthine fur- 

 nish yellow or reddish-yellow, the former when 

 mixed with Oocyan producing a beautiful dark 

 green ; Lichenoxanthine is believed by Dr. 

 Sorby to be a constituent of the shell of eggs 

 of a brick-red colour. The undetermined sub- 

 stance is believed in combination with others 

 to produce an exceptionally brown tint. Oo- 

 rhodeine is believed to be closely related to 

 Cruentine, and possibly derived from the red 

 colouring pigments of the blood, and further, 

 that the two Oocyans have some chemical re- 

 lation with the bile. The reader anxious to 

 go deeper into this interesting question may 

 be referred to Dr. Sorby's paper on the sub- 

 ject published in the Proceedings of the Zoo- 

 logical Society of London, 1875 (pp. 351-365). 

 Whether Dr. Sorby's very interesting lecture 

 upon the subject of the colouring matter of 



