[39] INSTRUCTIONS FOR COLLECTING MOLLUSKS BALL. 



quarter behiud the aperture. By applying tlie pressure of the extractor 

 carefully in this vicinity the attachment will give way and the extractor 

 may be withdrawn, bringing with it the soft portions of the animal. In 

 large and heavy shells, in which the muscular attachments are strong 

 and deep-seated and it is desired to obtain a good hold of the animal 

 in order to extract it from the shell, ordinary steel fish-hooks may be 

 used. These may be softened by heat, straightened out, and twisted 

 into a spiral of the proper form, and retempered. Then they can be 

 securely fastened to small wooden handles by the shank of the hook. 

 In this way the barb of the hook will assist in retaining the soft parts 

 on the extractor when it is withdrawn from the shell. Several German 

 firms advertise sets of implements for cleaning, cooking, and extracting 

 the animals from shells of mollusks, but it would seem to the writer 

 that any person of ordinary intelligence and some little mechanical 

 ingenuity, such as all naturalists are expected to possess, should be 

 able to provide himself with the necessary apparatus without purchas- 

 ing expensive paraphernalia of this kind. Shells which have no oper- 

 culum require merely to be cleaned after the animal has been removed, 

 and in the case of land and fresh-water shells this is usually a very 

 simple matter. Shells which possess an operculum should retain it in 

 the cabinet, as it is often of great value in determining the relations of 

 the species, since the operculum is a characteristic feature in the econ- 

 omy of the animal. It should be detached from the body of the animal 

 after the latter has been extracted from the shell, carefully washed and 

 cleaned, and if flat and horny may be dried between two pieces of blot- 

 ting paper, under a weight. This will prevent it from becoming con- 

 torted in the process of drying. For removing the thick incrustation 

 of lime and peroxide of iron which frequently forms upon fresh- water 

 shells, a few tools resembling engraver's tools or the little chisels in use 

 by dentists for excavating teeth are very convenient. A suitable tool, 

 however, can easily be made by softening and grinding down an old file 

 to a triangular point. A little experience wiU enable the collector to 

 become expert in scaling off the objectionable matter without injury to 

 the surface of the shell. 



N"aked slugs should be preserved in alcohol, after being sketched in 

 the living state. Some of the older naturalists had a way of skinning 

 slugs, inflating and drying the empty skins for preservation in their 

 collections, much as entomologists sometimes treat caterpillars; but 

 this ingenious device has nothing to recommend it to a scientific col- 

 lector, even if he has the dexterity to practice it. The internal shell 

 of such slugs as Limax may be represented in the collection if desired, 

 but, in any case, specimens should be carefully preserved in spirits. 



The bivalve shells, such as TJnio, if taken alive, may be left in the 

 sun for a short time, when they will usually open, and, the muscle 

 connecting the two valves being cut, the valves may be cleaned. It is 

 desirable for cabinet purposes to preserve the two valves in their 



