2l8 



Capsnlcs of Shark Eggs 



[Dec. 



to any visible degree. The pieces were then ground to a fine 

 powder. This was an exceedingly difficult task, owing to the 

 toughness of the material. The powder was grayish-black in color 

 for the skate capsules, and reddish-brown for the Port Jackson 

 shark capsules. 



IV. SOLUBILITIES OF THE CAPSULAR SUBSTANCE 



The solubiHties of the predominant material in both the Raja 

 and the HeterodonUis capsules are given in the following table. 



SolubiHties of the keratinoid suhstancc in the egg capsules of Raja erinacea 



and of Heterodontus philippi. 



From this table it is seen that the substance of both capsules is 

 very resistant to the action of ordinary solvents. The powdered 

 materials were insoluble in water, alcohol, Chloroform and ether. 

 They were soluble in both acid and alkaline solvents. The sub- 

 stance of the skate capsule was more soluble in alkaline than in 



' Slightly more soluble than in cold 10 per cent. hydrochloric acid Solution. 



* More soluble than in i per cent. hydrochloric acid Solution. 



' Dissolved completely on long Standing. 



° Samples of both the powdered and the whole capsules dissolved on boiling, 

 in twenty minutes, giving a deep wine red colored liquid. 



' Much less soluble than in potassium hydroxide Solution. The Solution had 

 a wine red color by reflected light. 



