NO. 4 FORAMINIFERA CUSHMAN II 



When shallower waters are studied, it is possible for the individual 

 to make very excellent collections. The " bulldog " snappers, which 

 are so devised that they grab up a tea-cup full of the bottom material, 

 can be used from a small boat to a considerable depth. By adding a 

 weight to this apparatus, it is possible to obtain excellent samples, 

 even in two or three hundred fathoms. This method has been used 

 in the West Indies and ofif the coast of Florida, as well as in the 

 Pacific, with excellent results. It is also possible to obtain a con- 

 siderable number of foraminifera from beaches where they are often 

 left by the receding tide, in some regions very abundantly. 



Preserving. — If it is desirable to study the living animals, it is 

 necessary to preserve them in some form or other. If the cell contents 

 are to be studied special reagents such as are used in general zoological 

 work must necessarily be used. Formaldehyde should not be used as 

 it tends to dissolve the lime content of the tests. As a general pre- 

 servative, therefore, alcohol is much better. If only the tests are to 

 be studied one of the best methods of preserving the material is to 

 wash it at once in fresh water, and then dry the material, preserving 

 it in bottles or boxes for future use. 



Washing. — For the examination of the foraminifera clean tests 

 are necessary. In order to get these the dredged material, which con- 

 tains mud and fine sand, should be washed. This is best done by means 

 of nested sieves, such as are obtainable at most laboratory supply 

 houses. Brass sieves w4th meshes of 200, 120, 80, 40, etc., to the inch 

 can be obtained. For more practical purposes sieves with 40 and 

 80-mesh to the inch are sufficient. The mud is placed directly in the 

 top sieve, and a stream of water with a fine spray played upon the 

 material. If the sieves are shaken so that the material is kept in motion 

 the finer particles will be washed through readily. The resulting clean 

 foraminifera can then be dried. It is sometimes more satisfactory 

 to wash material through the coarsest sieve first into some sort of 

 retainer, and then this again passed through the finer sieves. By this 

 means the finer meshed sieves do not clog with the material. 



Sorting. — After the material is washed it often helps in the 

 examination if preliminary sorting can be done. There are different 

 methods of doing this. One is that called " spinning." By this method, 

 the material is put with clean water in a plate or watch glass or in 

 any dish with water so that a circular motion can be set up. This 

 is the old method by which gold was " panned " by the miners. The 

 gold dust was heavier than the sand and came to the middle of the pan. 

 In the case of the foraminifera, however, they, being lighter than the 



