VAUIOIJS INVERTEBRATE ANIMALS. Il7 



Parasitic worms may be thus preserved. Wash the specimens 

 with a camel's-hair brush dipped in 10-12 per cent, solution of nitric 

 acid. Place them in 40-50 per cent, alcohol for one or two days ; 

 then in 70-80 per cent, for seven to ten days ; then in 90 per cent. 



Crustacea. 



Crustacea of all kinds are best preserved in spirit. They may be 

 simply placed in it living ; but, if possible, it is better to kill them 

 in weak spirit (30 per cent.), and then transfer them to stronger 

 spirit (70 per cent.) for preservation. 



To avoid the casting off of the appendages of the larger marine 

 Decapods, they should be allowed to die in fresh -water, care being 

 taken not to allow them to remain in it longer than is necessary, 

 as it causes a distortion of the membranous appendages. 



Hermit-crabs should be killed in fresh-water, when they will come 

 out of their shells ; if killed in alcohol, it is often impossible to 

 extract them without injury. The shells should be preserved with 

 any commensals, as Anemones, Hydroids, etc. 



Minute and soft-bodied forms are often quite well preserved by 

 simply killing them in spirit ; but, when possible, it is often worth 

 while to fix a portion of the catch with corrosive sublimate dissolved 

 in sea-water, or in equal parts of sublimate solution and strong 

 spirit. 



Large Crabs and Lobsters can be preserved dry : their colours are 

 best kept by their being dried away from strong sunlight. Specimens 

 of the same species should also be preserved in alcohol. 



Formalin should, as a rule, be avoided for Crustacea. It tends 

 to render the specimens brittle, and dissolves out a part of the 

 calcareous salts to form a flocculent precipitate. For small and 

 soft-bodied forms, however, a mixture of equal parts of 5 per cent, 

 formalin and strong spirit has been employed with success. 



Fresh-water Crustacea, Crabs, Crayfish, Prawns, and the more 

 minute forms are well worth collecting in nearly all parts of the 

 world. Unless the collector has opportunities for dredging, or has 

 experience in shore-collecting, marine Crustacea, especially the larger 

 and more conspicuous kinds, are less likely to be of interest. 



