ON SPONGIOPORPHYRIN. 345 



examining Spongiopoi'phyrin, but I am now sure that such 

 is not the case. 



On comparing Spongiopoi-phyrin with polyperythrin, 

 which I have shown reasons for supposing to be haematopor- 

 phyrin/ with antedonin, which is shown in sp. 10^ drawn 

 from a specimen given me by the late Professor Moseley, 

 and with, in fact, all the pigments which have been described 

 up to the present time, I am quite sure we have in Spongio- 

 porphyrin a pigment which is new to biology. 



I hope soon to be able to say something more about the 

 chemical characters, as well as about the spectrophotometry 

 of this pigment. In being apparently so easily isolated and 

 purified, as compared with pigments which are mixed with 

 fat, or even of a fatty nature, it promises to give interesting 

 results when submitted to a thorough chemical examination. 



EXPLANATION OF PLATE 16, 



Illustrating Mr. C. A. MacMunn's paper " On Spougiopor- 

 phyrin : the Pigment of Subcrites Wilsoni." 



(The scale atlaclied is one of wave-lengllis in 100,000lIi nun.) 



Sp. 1. — Spectrum of a rectified spirit and nitric acid extract, of Spongio- 

 por|)liyrin. 



Sp. 2. — Tlie same; sliallower de|)tli or weaker solution. 



Sp. 3. — An aqueous and caustic soda solution of Spongiopor])livrin. 



Sp. 4. — Tiie same; shallower depth or weaker solulion. 



Sp. 5. — Spongioporplijrin in water acidulated with iiydrocliloric acid. 



Sp. 6. — Tlie same ; shallower deptli or weaker solution. 



Sp. 7. — Neutral aqueous solution of Spongioporphyrin. 



Sp. S. — Spongioporphyrin in neutral state mounted in Canada balsam. 



Sp. 9. — Action of excess of nitric acid on an aqueous solution of Spoimio- 

 por[)hyrin. 



Sp. 10. — Moseley 's antedonin, mounted in balsam. Eioin a specimen |)ut, 

 u|) by tlie late Professor Moseley when on the " Cl!allppi,^er." 



