MOLLUSCA. 235 



fresh water, the salt remaining soon attracts moisture, which 

 speedily destroys the ligaments and epidermis. 



The land shells are more within the reach of the scientific 

 collector. To obtain these, he has only to examine the cre- 

 vices of rocks, the trunks of trees, decayed wood, moss, and 

 brushwood. In summer, after a shower, the land shells are 

 most easily procured. The animals come forth to feed on 

 the moistened blade, and at that time, from their motion, 

 may be very readily perceived. 



The land shells are very easily preserved. Almost all that 

 is required is the extraction of the animal. 



The fresh water shells, though less difficult to procure than 

 the sea shells, require more trouble than the land shells. A 

 piece of gauze spread over a ring attached to the end of a 

 staff, forms a very convenient net for fishing fresh water 

 shells. By means of this net in the drought of summer, al- 

 most all the different species of fresh water shells may be 

 obtained with ease. 



The fresh water shells are frequently covered over with 

 slime or mud, which must be removed by a brush ; and the 

 animal may be extracted after the shell has been plunged in 

 boiling water. 



Before closing our remarks on the important group of 

 animals to which we have been directing the attention of 

 the reader, we shall dedicate a few paragraphs to a brief 

 notice respecting Fossu, SHELLS. 



Besides the shells which are found on the land and in our 

 lakes, rivers and seas, and termed RECENT SHELLS, there are 

 relics of many species found in our marl pits and limestone 

 rocks, always somewhat altered, and which are denominated 

 FOSSIL SHELLS. While the shells of the former class have been 

 eagerly sought after, few conchologists, previous to the be 



