414 A. EARLAND ON FORAMINIFERA. 



not show, provided the mount is thoroughly dried before the 

 balsam is added. 



When searching for specimens of a particular form known to 

 occur in a gathering, much labour may often be saved by 

 recourse to some mechanical process for separating it from its 

 fellows. For instance, if the form required is of a more or less 

 spherical shape, it is possible to obtain all the rounded foramini- 

 fera in a gathering by sprinkling the material on the surface of a 

 sheet of glass or highly glazed paper, which is then gradually 

 tilted until they roll off into another sheet prepared for their 

 reception. If the process is carried farther, the less rounded 

 forms will roll away, until at last only the very flat forms, such 

 as Cornuspira, Planorbulina, etc., are left. This process naturally 

 answers best with the coarse material containing large forms, but 

 if carefully done it is possible even with the finest material — 

 although in this case it is more useful as a means of separating 

 the flat forms only, such as Spirillina, etc. 



In the case of fossil foraminifera from many strata, and more 

 rarely in the case of recent foraminifera, the internal chambers 

 have become filled with mineral matter, thus furnishing perfect 

 internal casts showing the shape of the sarcode body of the living 

 animal. In fossils the mineral is usually pyrites, while in recent 

 casts it is usually glauconite. The cast can be obtained by 

 removing the calcareous shell of the foram by means of very 

 dilute nitric acid, which should be so weak as to be barely per- 

 ceptible to the taste. If the process of decalcification proceeds 

 too rapidly, the effervescence will destroy the cast. When all the 

 carbonate of lime is removed, the casts, which are extremely 

 fragile, can be removed with a pipette and mounted in the 

 ordinary manner. 



In conclusion, I may add that the sarcode body may be observed 

 and studied in the living animals, which may be obtained by 

 washing algse, etc., from lowest tide pools in a basin of water. 

 The washings should be placed in a bottle, and the foraminifera 

 will in a few hours be seen attached to the sides near the bottom. 

 They can be removed with a pipette, and if the water is properly 

 aerated, a supply can be preserved in a bottle for some time, 

 keeping the bottle in a rather dark corner. 



