TAXIDERMY. 91 



Slugs, cuttle-fish, dorides, &c. can only be pre- 

 served in spirits ; it is the same with animals which 

 inhabit shells, but we ought to preserve the shell. 



The greater part of these animals dwell in the 

 sea, others in fresh water, and a third part are found 

 on land, in cool damp places, and almost always in 

 the shade. We distinguish them from each other 

 by the denominations of marine shells, testae marinoe, 

 fluviatiles (river shells), and terrestres, or land shells. 

 These last are very much sought after, many of them 

 fetch a great price amongst amateurs, because of 

 their rarity. We must recommend to travellers, if it 

 is only as a secondary consideration, to search parti- 

 cularly for terrestrial shells. When they have found 

 them, they must place them in any sort of vessel, 

 and pour boiling water on them ; after a moment 

 they can tear the animal from its shell with a pin, 

 or the tooth of a fork ; they may do the same by 

 fresh- water and sea shells. 



Marine shells, bivalves or univalves, are all co- 

 vered by a species of coriaceous envelope, (drap 

 mariU) ) or other foreign substances. We take these 

 off with nitric acid or aquafortis, with which we im- 

 bue them exteriorly with a horse hair pencil, some 

 seconds after we put them into a vessel full of soft 

 water, then brush them ; the asperities will discover 

 themselves, and we again put nitric acid on those parts 

 which do not appear to belong to the shell. When 

 all the foreign substances are taken away, we give 



