298 THE FOEAMINIFEKA 



on its retreat the shells are left behind on the ripple- 

 marked sands, often filling up the furrows and mark- 

 ing the strand with white lines composed of their 

 minute shells. In proceeding to collect this material 

 we may use a large spoon to scrape up the surface 

 layer of these streaks, and to fill some muslin bags 

 with which we should be provided. This material 

 will possibly require to be further cleaned and 

 separated — first, to get rid of the salt from the 

 water, and secondly, to divide the shells from the 

 sandy portion, of which latter there will be a varying 

 proportion, according to the purity of our foraminiferal 

 deposit and the care we bestow upon it in collecting. 

 Sometimes it is found necessary to separate the 

 lighter Foraminif era from the larger and heavier forms, 

 by a process called ' floating.' This is done by 

 gently warming the dried material and then throwing 

 it upon cold water, when the smaller or lighter air- 

 filled chambered shells, as Lageiia, Miliolina, and 

 Glohigerina, will remain on the surface. These float- 

 ings can be poured on to a fine muslin sieve, which 

 will retain the shells and allow the water to pass 

 through. The material can then be dried for the 

 selection and examination of species. In this part of 

 the work the sieves used should have copper sides, as 

 these will not rust nor warp, as iron or wood. A 

 further separation of the sunken or heavier foramini- 

 feral shells may be ejected by stirring up the material 

 in water and decanting the lighter portion before it 

 can subside. 



Another method of separating the lighter forami- 



