The Shell-Collector's Handbook. 35 
needles stuck head first into handles. The animals of 
the larger specimens will come out easily this way ; 
but those of the smaller ones sometimes break inside. 
To obviate this difficulty, these last should be killed in 
boiling water, to which some salt has been added. 
This renders their extraction much easier. 
The confervoid growth often found on the shells of 
water-snails should be removed by means of a tooth- 
brush, dipped in pure water, with plenty of elbow- 
grease. Should, however, pure water fail for this 
purpose, a very weak solution of potassium hydrate 
may be used; but the collector must be careful in 
employing this method, for the caustic nature of the 
alkali is apt to dissolve away the periostracum of the 
shell, in which the colouring matter alone exists. 
In the case of a bivalve the animal is extracted by 
the use of the small blade of a pocket knife, or, better 
still, a small dissecting scalpel, taking care, in doing 
so, not to cut the ligament which holds the valves of 
the shell together. Then, having well cleaned the 
shell, twist it up tightly in paper, so that the ligament 
may dry and the valves become firmly set. If this is 
not done, the valves will gape. 
Slugs should be killed by drowning, and their 
mucus removed by careful rubbing with a cloth. 
They may may then be transferred to glass tubes 
filed with some medium for their preservation. 
Several media for this purpose have been recom- 
mended. I use a weak solution of chloride of zinc ; 
but turpentine, or a mixture of equal parts of 
glycerine and methylated spirit, may be used in the 
absence of this. Mr. Woodward employs a solution 
; D 2 
