and Laboratory Methods. 1957 



By keeping them for a short time in a dry place, the animal will retire far within 

 the shell. Then they should be put into 25 per cent, alcohol for a day or two. 

 If to be left longer in the alcohol, the strength should be increased. Twenty- 

 four hours, however, in the alcohol is all that is necessary. Then they can be 

 dried in the air without leaving any offensive odor. Either before or after 

 drying they can be cleaned by putting them in a bottle with some fine, clean 

 sand and shaking them together until all the dirt has been removed by the sand. 



Specimens of land snails desired for anatomical purposes should be drowned 

 before being put into the alcohol or formaldehyde, otherwise they retire as far as 

 possible within the shell and are more difficult to dissect in this contracted con- 

 dition. By drowning, they die fully extended and can then be put into the pre- 

 servative. It takes about a day to kill a snail in this way. The alcohol at first 

 should be greatly diluted, not stronger than 25 per cent., after a day or two the 

 specimens should be removed to 50 per cent, alcohol, and later to the undiluted. 

 Formaldehyde, '2 per cent, dilution, is an admirable preservative for material of 

 this kind. 



With the exception of the larger species of Planorbis, which are more easily 

 cleaned by boiling, it is practically immaterial whether the fluviatile univalves 

 are boiled or put directly into diluted alcohol. In either case there is no diffi- 

 culty in extracting the animals. The minute species are treated the same as 

 the small land shells. In the operculate species, it is desirable to retain the 

 opercula of, at least, part of the specimens. While it adds to the labor, it in- 

 creases the value of the specimen, if it is always done. These are easily 

 removed from the animal and, after being cleaned, should be put inside the 

 shell and the aperture plugged with cotton. All the foreign matter both inside 

 and outside of the shell should be removed by thorough washing. All the water 

 species are apt to be more or less incrusted with deposits of lime or oxide of 

 iron. These can be removed by immersing them in oxalic acid. Care should 

 be taken not to prolong the operation, or the texture of the shell may be in- 

 jured. Elbow grease is the most effective agent for making good specimens. 

 When that fails, use the acid. The Aiicyli are always more or less coated in 

 this way, and can easily be cleaned by floating them for a few seconds on the 

 acid, upside down, and then gently brushing them off with a soft brush while 

 held on the tip of the finger. 



The larger bivalves should be well washed and, if necessary, scraped off with 

 the knife as soon as taken, care being taken not to injure the epidermis. 



They can be boiled, if desired, when the shells will open and the animals 

 easily removed. But as a rule it is more convenient to cut the muscles, which 

 hold the valves together, with a thin bladed knife and scrape the animal out. 

 Care should be taken not to break the edge of the fragile species when inserting 

 the knife. All traces of animal matter should be removed, and after a thorough 

 washing the valves tied together with a string until thoroughly dried. Never 

 use colored twine for this purpose, as it is apt to stain the shells. Any surface 

 incrustation can be removed either with oxalic or muriatic acid. The latter is 

 more convenient for the larger species, and can be applied with a small brush. 

 It does not bite the fingers, so that it can be used freely. Care, however, must 



