MONOGRAPH OF THE EXISTING CHINOIDS. 751 



On the alcoholic solution being rendered alkaline by the addition of ammonia, 

 it changes its color to a deep violet, and a flocculent purple precipitate is formed 

 in it, which can readily be separated by filtration. The precipitate when dried 

 appears as a violet amorphous powder which is insoluble in alcohol and oil of 

 cloves, and can thus be rendered transparent and mounted in Canada balsam as 

 adhering to the filter paper. This precipitate when dried yields the same spectrum 

 as it does when suspended in solution, consisting of two bands. 



The dried precipitate is insoluble in water, ether, and alcohol, but soluble in 

 acidified alcohol, and then gives the original acid spectrum, and when this solution 

 is carefully neutralized the original three-banded spectrum returns; but Moseley 

 obtained it only faintly. Though a very large quantity of precipitate was removed 

 by ammonia from a strong and original alcoholic solution, the solution still 

 remained of a vivid color and gave its three bands. It was only after continuous 

 addition of ammonia that the whole of the coloring matter was precipitated. 



The coloring matter appears to require a proportionately increased quantity 

 of ammonia to precipitate it as the solution becomes weaker. Both the dried color- 

 ing matter and the alcoholic solution have maintained their color and properties 

 unimpaired after a lapse of two years. 



Both pentacrinin and antedonin seem to be widely diffused in immense quanti- 

 ties throughout the tissues of the crinoids in which they occur. 



Dr. C. A. MacMunn studied the coloring matter of a few species of comatulids. 

 In particular Antedon bifida was examined, in order to settle the question of the 

 presence of symbiotic algse in the sacculi, this interpretation of these organs having 

 been advanced by Vogt and Yung and vigorously denield by P. H. Carpenter and 

 by Bury on histological grounds. 



MacMunn says that the " pyriform oil cells " of Thomson, which were supposed 

 to be migrating amoeboid spores of symbiotic algse by Vogt and Yung, were easily 

 seen by him, but that they are totally different in shape and structure from any 

 symbiotic algae which he has seen. They appear to him to be outgrowths from the 

 surface of the pinnules, the flask-shaped ones being attached by the part repre- 

 senting the neck of the flask. Some which he measured varied in size from about 

 10 (A to 5 (j. in their long diameter, and from 6.25 [x to 5 \>. in their short diameter. 

 They are mostly homogeneous and yellowish green in color; some seemed to have 

 granular contents, but these were of exceptional occurrence. MacMunn failed to 

 find either starch or cellulose in these pyriform bodies. 



Glycerine, water, and alcohol readily extracted the red coloring matter, but ether 

 failed to do so, as it only became faintly yellow. The glycerine extract was a fine 

 rose color. Spectroscopically a deep layer transmitted red and a little green, and 

 in a shallow layer an ill-defined shading occupied the other half of the green. 

 Ammonium sulphide discharged the color, leaving a faint yellowish tint, but no 

 absorption bands were visible. Hydrochloric acid changed the color to pale yel- 

 low, the solution showing no bands, and ammonia changed it to a faint rose tint. 



The aqueous solution gave the same kind of absorption as the glycerine solu- 

 tion, and showed in a thin layer only a faint shadow in the green. Ammonium 

 sulphide discharged the color of such a solution, leaving only a faint reddish- 



