THE MOLLUSCA 961 



The apparatus for collecting is very simple. 



It is necessary to have a dipper and, if possible, a small dredge. 

 The dipper is made from an ordinary tin one by removing the 

 bottom and substituting one of fine wire cloth. By removing the 

 end of the handle, the dipper can be slipped on the end of a cane 

 or pole when in use. This is useful not only for reaching the larger 

 specimens from the shore or boat, but especially for sifting the mud 

 and sand from the bottom, where a multitude of small species live, 

 which otherwise would not be found. It will be found more con- 

 venient to empty the contents of the dipper, when thoroughly 

 washed out, into a pail or small bag, and carry the whole mass 

 home before undertaking to pick out the shells. If attempted in 

 the field, many of the smaller and more desirable things are apt to 

 be overlooked. By spreading the mass out in the sun for a short 

 time, it wUl become dry and friable so that the shells can be easily 

 separated and picked out. An ordinary reading glass is very useful 

 for the detection of the more minute forms in sorting over such 

 material. 



Many desirable species live in water too deep for the convenient 

 use of the dipper, and for these it is necessary to have a small 

 dredge. One with an aperture of 9 by 6 inches is as large as can 

 be used satisfactorily by a single person in a boat. 



Several small bags and a number of wide-mouthed bottles and 

 small vials should be carried, so that the specimens from different 

 locahties may be kept separate. Care must be taken to keep the 

 more fragUe species separate from the heavier ones, otherwise they 

 are likely to be damaged in moving about. For the same reason 

 it is better to fill the bottles partially with water while in the field, 

 as the mollusks then attach themselves to the glass and are less 

 likely to be broken. It is not necessary to take alcohol into the 

 field. 



Specimens to be kept for anatomical purposes may be preserved 

 in alcohol, which at first should be greatly diluted, not stronger 

 than 25 per cent; after a day or two the specimens should be re- 

 moved to 50 per cent alcohol, and later to the undiluted. Formal- 

 dehyde. 2 per cent dilution, is an admirable preservative for ma- 

 terial of this kind. It should not, however, be used when it is 



