142 HOW TO PREPARE FORAMINIFERA. 



through this zinc sieve must be well and carefully washed, and 

 looked over when dry, as it will contain the largest forms, some 

 of which, as JVodosaria, Dentaliiia, etc., may be nearly half-an- 

 inch long. 



A large cup-full of the fine sifted powder must now be put into 

 sieve " number one," and a good stream of clear fresh water 

 be allowed to wash it until all signs of milkiness have disappeared, 

 and the water runs away quite clear. Do not use either fingers or 

 spoon to stir up the material, but let the stream of water from the 

 india-rubber tube do all the work, directing it so as to move the 

 powder well about. When the water runs away clear, wash all 

 into a corner of the sieve, drain, and tip out the chalk powder on 

 to a plate to dry thoroughly in the oven. Repeat this process 

 until all is washed ; and when dry, and cold, sift into sizes for 

 examination. The finest siftings will probably be the richest in 

 species. 



If the chalk-powder is good and the washing properly done, 

 a considerable portion will be found to consist of Foraminifera, 

 Ostracoda, Sponge and other spicules, etc., the remainder being 

 sand, etc. 



If sponge spicules or other siliceous organisms only are being 

 sought for, pour dilute Hydrochloric Acid over the Chalk-powder, 

 and let it remain for a day or two to remove all the lime ; after 

 which pour off the acid, and wash well with clean water until every 

 trace of the acid is removed ; then dry, sift, and examine. 



As these Foraminifera are fossil, and mostly siliceous, they will 

 not " float," but the washed material (after drying) must be 

 examined under the microscope, and the individual shells picked 

 out. There is no royal road for doing this. It is best done by 

 means of a fine miniature red sable pencil, wet with clean water, 

 and just passed through the lips so as to bring it to a fine point, 

 and prevent its being too wet. A full description of the modus 

 operandi^ either for fossil or recent Foraminifera, is given near the 

 end of the present article. 



Fresh dredgings of sea-mud, shore-mud, etc., may be 

 treated thus : — 



If principally sand, the process described in the first paper 

 (page 26) must be followed throughout. 



If soft mud, a small quantity should be put into a suitable 

 vessel (say a large wide-mouthed jug), full of fresh water, and be 

 well stirred up to about the consistency of cream. Sieve "number 

 one " being ready, and well wetted, should then have a little of 

 this cream poured into it, and upon this a good stream of fresh 

 water should be allowed to run so as to wash the mud, until the 

 water runs away clear ; after which the contents of the sieve may 



