28 FORAIkllNIFERA. 



the bottom, and then, by means of a " washing-bottle " (or its 

 equivalent), begin at the top, and wash the shells to the bottom 

 of the filter, using as little water as may be. The filter must then 

 be carefully and perfectly dried, after which the " floatings " are 

 ready for examination. If the different operations just described 

 have been properly performed, the Foraminifera will be found 

 clean and bright, and fit for mounting. 



Sometimes, however, it happens that a quantity of minute 

 fragments of algae, or vegetable matter, which was present in the 

 " gathering," has also floated — which quantity may be much in 

 excess of the shells, and may even be firmly adherent to them. 

 This may be almost, if not entirely, removed, by carefully 

 boiling the floatings (after drying), in the common liqtwr-potassce, 

 strength B.P., as sold by chemists, after which the floatings must 

 be well washed in clean water, so as to remove every trace of 

 the potash (boiling in, at least, two waters is best), then dried, 

 re-floated in a beaker, and dried again. The result will always 

 amply repay for the additional trouble it entails. The floatings 

 are best kept in flat, " shouldered " pill-boxes, care being taken 

 to label each lot as it is done, so as to avoid mistakes respecting 

 locality, etc. 



It will sometimes be found, where the sand is very fine, 

 {e.g.^ sponge-sand), that the air clings so tenaciously to its surfaces, 

 that a quantity of it will also float with the Foraminifera. I 

 have frequently overcome this annoyance by blowing off the 

 floatings into a pint beaker-glass, and after nearly filling this, 

 have well stirred all up, and allowed a sort of second floating 

 to occur, by waiting four or five minutes, and then blowing off 

 the scum from the beaker into a filter-paper, which was dried, 

 etc., as before described. But when doing this — and it is often 

 worth doing — the sand which settles to the bottom of the beaker 

 should also be dried and examined, as generally it will be found 

 to contain many shells. 



The various operations just described may be now summed up 

 thus (for Shore-sand and such like) : — 



I. — Well wash in fresh water to remove the salt. 



2. — Dry perfectly^ and allow to get cold. 



3. — Sift (sieve No. 50 or 60). 



4. — Float the fine material in cold, fresh water. 



5. — Dry the floatings. 

 Perhaps it may also be found needful to — 



6. — Boil the floatings in liquor-potassa', B.P. 



7. — Wash away every trace of potash. 



8.— Dry. 



9. — Re-float in a beaker. 

 10. — Dry again, ready for mounting. 



