50 



Cincinnati Society of Natural History. 



LimndsidcB are stained with ferruginous and other matters that no 

 amount of washing will remove. If such shells are immersed for a few 

 moments in the oxalic acid solution, these stains will readily wash off, 

 and a judicious use of the acid does not harm the shell in the least. 

 If it is desirable to remove these stains from Unionidce, I should drop 

 them into the acid immediately after washing, and before scalding out 

 the animal, the presence of which prevents the acid from coming in 

 contact with the nacre of the shell, which it will slightly dim if the 

 shells remain in it for too great a length of time. It is often the case 

 among the southern shells that these stains have so obscured the real 

 characteristic markings of the shells as co have made it one of the 

 chief causes of so much synonomy. If dead shells must be taken, or 

 musk-rat shell heaps explored, which is sometimes the case, a judi- 

 cious nse of the acetic acid will remove stains, and in many cases 

 fairly well restore the original appearance of the nacre. 



The black and dirty univalves which we generally receive in ex- 

 change, and the dirty TJnionidm, maybe perfectly cleaned by judicious 

 use of these acids. But while they are to the careful student collector 

 an inestimable boon, a careless or injudicious use of them will ruin 

 every shell so treated. I consider a dirty shell as useless and worthless 

 for cabinet purposes. I have many such, and am obliged to receive 

 them or none, and while shells so received may often be cleaned so as 

 to be made presentable, the proper time to do it is when the shells are 

 collected. 



I have to add, that where the Strepomatidce are collected in alcohol 

 or any preservative solution in quantity, they ma}' be subjected to the 

 cleaning process whenever opportunity offers. It will generally only 

 be necessary to immerse those having the worst stains in the acid for 

 a few moments, and then wash and rinse them thoroughly. Many 

 Uniones and univalves are much improved, and given the appearance 

 they have when in the water, or when wet, by rubbing them with a 

 clean sponge, on which are a few drops of boiled linseed oil. " Woolly" 

 shells, or those with a soft epidermis, ma}' be excluded from this list. 



Many of the Unionidce also have a very highly polished epidermis, 

 and when clean look as well drv as wet. The use of the oil is a great im- 

 provement to some species, and it preserves all fresh water shells; but 

 as before stated, it must be kept off of land species. Physa, Limn&a, 

 and Planorbis must be scalded, and the animals removed with the land 

 shell hooks, and they should afterward be treated in the same way. If 

 stained, treat them with the oxalic acid, using it judiciously, and you 



