SLUGS. 91 
then take the slug you wish to preserve, and let it 
crawl on a long slip of card. When the tentacles 
are fullyextended, plungeit suddenly into thesolu- 
tion; in a few minutes it will die, with the ten- 
tacles fully extended in the most life-like manner; 
* so much so, indeed, that if taken out of the fluid 
it would be difficult to say whether it be alive or 
dead. The slugs thus prepared should not be 
mounted in spirit, as it 1s apt to contract and dis- 
colour them. A mixture of one and a half parts of 
water and one part of glycerine I find to be the 
best mounting fluid. It preserves the colour 
beautifully, and its antiseptic qualities are unex- 
ceptional. A good-sized test-tube answers better 
than a bottle for putting them up, as it admits 
of closer examination of the animal. The only 
drawback to this process is, that unless the solu- 
tion is of sufficient strength, and unless the ten- 
tacles are extruded when the animal is immersed, 
it generally, but not invariably, fails. Some slugs 
appear to be more susceptible to the action of 
the Huid than others; and it generally answers 
better with full-grown than with young specimens. 
But if successful, the specimens are as satisfac- 
tory as could be desired; and, even if unsuccessful, 
they are a great deal better than those preserved 
in spirit ; for, although the tentacles may not be 
completely extruded, they are more or less so.” 
