24 JOURNAL OF. SCIENCE. 
It is usually sufficient if the liver, reproductive organs, &c., are 
removed through an aperture made in the membrane which 
unites the carapace withthe abdomen. After 3 to 5 days remove 
from the glycerine fluid, allow to drain thoroughly, and after 
some days paint over with a thinnish size made from isinglass or 
gelatine. This method retains, to a great extent, the natural 
colour and flexibility. For the smaller and uncalcified speci- 
mens (shrimps, amphipods, &c.), use picric acid, followed as usual 
by alcohol ; or, if specially good specimens are desired, place in 
the smallest possible quantity of water and add a few drops of 
osmic acid. When the specimen has acquired a light brown 
colour (the time will vary according to the strength of the acid) 
transfer to weak alcohol, changing several times and gradually 
increasing the strength. Microscopic crustacea may often be 
beautifully preserved in the same way, the whole operation 
being conducted, if possible, on a slide under the microscope. 
They may then be mounted either in glycerineorin Canadabalsam. 
INSECTS (including larve) MYRIAPODA AND ARACHNIDA.— 
For internal structure, picric or chromic acid for 2-3 hours, fol- 
lowed by alcohol. For external characters the glycerine method 
may be found useful in some cases, but I have not made 
sufficient experiments in this direction to speak with certainty. 
LAMELLIBRANCHIATA.—Alcohol, of about 70 per cent., for 
a day, then strong alcohol. Specimens may be killed in the 
expanded condition by placing them in hot water, or in vinegar ; 
but these methods do not always succeed. 
GASTEROPODA.—Here again there seems to be nothing 
better than weak followed by strong alcohol. The larger the 
specimen the greater should be the quantity of alcohol, and in 
very bulky species, such as the black sea-slug Parmophorus of 
these coasts, it is advisable to make an incision through the mantle, 
so as to allow the spirit to make its way immediately among the 
viscera. For killing Gasteropods in the expanded condition 
different methods must be employed, according to circumstances. 
For Nudibranchs (Doris, &c.), allow to expand in a small vessel 
of sea water, and add potassium bichromate solution, little by 
little, with a pipette. The fluid gradually diffuses into the 
water, and if care is taken not to transfer the animal to spirit 
until it is quite dead, very good specimens may be obtained. 
The Pulmonata are best killed by placing them in a tumbler 
or other vessel with a straight rim, quite full of water, and then 
placing a plate over it. The point is to ensure entire immer- 
sion. It takes many hours to kill snails, slugs, &c., in this way, 
but they almost invariably die in a fully extended condition. 
Here again care must be taken that the animals are quite dead 
before being placed in alcohol, as otherwise they will contract. 
CEPHALOPODA.—Make an incision into the mantle, and 
place in alcohol. In the case of large specimens, or if several 
small specimens are placed together in a jar, it is unnecessary to 
use weak spirit first ; otherwise, as in other cases, this is advisable. 
TUNICATA.—Picric acid or potassium bichromate, fol- 
lowed by alcohol ot gradually increasing strength. 
