MOLLUSCA OF MICHIGAN— WALKER. 



451 



can be done after boiling, or a few days in alcohol. As these are usually 

 too small to be easily tied together to keep the valves from gaping, each 

 specimen, while the hinge is flexible, should be closely wrapped up in a small 

 piece of tissue paper until completely dry. 



While it is not usually desirable to keep "dead'' shells for the cabinet, 

 occasionally it is necessary. In such cases, the color can be in some measure 

 restored by washing in a solution of paraffine and gasoline (a square inch 

 of the former in half a pint of the latter) . 



A good collection is characterized by two essentials: 



First. The careful selection and preparation of the specimens them- 

 selves. 



Second. Absolute accuracy in the matter of the localities from which they 

 come. 



There is little excuse for having poor and ill-cleaned specimens. There 

 is none at all for failure to keep accurate records of the collector's field work. 

 A drawer of a common species, such as Polygyra alholahris, without any in- 

 dication from where they came, even if well cleaned, would be absolutely 

 without value. Such a drawer of any of our species from fifty or one hun- 

 dred different localities, definitely indicated, would be a valuable contri- 

 bution to the conchology of any state. 



Specific names can be supplied or corrected any time, but a mistaken or 

 erroneous locality cannot ever be corrected. The collector therefore should 

 be careful never to trust to memory for facts of this kind. 



Both in collecting and cleaning, the specimens from each locality should 

 be kept carefully separated and labeled. Too much importance cannot be 

 given to this point. The study of the geographical distribution of the mol- 

 lusca is one of the most important branches of conchological work, and this, 

 to be of any value, must be based on absolutely accurate work on the part 

 of the collector. 



ARRANGEMENT OF THE COLLECTION. 



The manner of casing and arranging the collection is largely one of in- 

 dividual preference. A catalogue, however, is essential, and it is better to 

 begin systematically in this particular and thus avoid the necessity of doing 

 it all over again, when the collection begins to assume considerable size. 

 There should be a serial catalogue and a card catalogue. Each addition to 

 the collection should be numbered as soon as received and entered in the 

 serial catalogue, which should be a book ruled in as many columns as the 

 collector desires. A convenient form is as follows: 



Serial 

 No. 



No. of 

 Spec. 



Name. 



From whom 

 Received. 



Locality- 



Remarks. 



1 



5 



Pol ygyra 

 albolabris (Say) . 



John Jones 



Ann Arbor, 



Mich. 





The card catalogue is convenient in a small collection 

 lutely necessary in a large one. 



The cards should be of uniform size for convenience in handhng 

 42 



It becomes abso- 

 If it is 



