VARIOUS SOFT-BODIED INVERTEBRATE ANIMALS. Ill 
sea -water, and then killed with concentrated acetic acid or boiling 
sublimate. The larger forms may be killed in from 1 to 5 per 
cent, chromic acid. 
Pteropods are preserved well in Perenyi's fluid for fifteen minutes, 
whence they are passed to 50 per cent, alcohol. Gymnosomatous 
forms should be first narcotized with 1 per cent, chloral hydrate, and 
then killed in acetic acid or sublimate. 
Decapod Cephalopods may be fixed directly in 70 per cent, alcohol, 
if an opening be made on the ventral surface to allow the alcohol to 
reach the internal parts. After twenty-four hours the alcohol 
should be poured off and replaced by a fresh quantity. After three 
days' immersion in this second quantity of alcohol, it is recommended 
that Cephalopods be preserved in 5 per cent, formalin. Formalin 
does not destroy the pigments of the integument. 
