[37] THE PRESERyATION OF MARINE ANIMALS HOVEY. 



over it a quantity of concentrated acetic acid at least as great as the 

 water in the dish. Then the liquid is removed by means of a siphon 

 and chromic acid of 1 per cent substituted therefor. Then carefully 

 try to give the animal a lifelike appearance by flattening the foot on 

 the bottom of the receptacle and arranging the cephalic lobe so that 

 it rests easily rolled up in conical shajje. In this manner it should 

 harden, and after half an hour the chromic acid should be siphoned off' 

 and weak alcohol introduced. The animal must be suspended in the 

 final receptacle. 



Fteropoda. — The Hyaleidse are placed in a little water and allowed to 

 expand the two wings, when saturated sublimate solution is poured over 

 them. After a few minutes they are washed and placed in weak alco- 

 hol, and so on. Criseis acicula is well prepared by killing it with 

 alcoholized sea water. 



Cymbuliidse are very well killed in Perenyl's solution, where they may 

 remain fifteen minutes before they are transferred to 50 per cent alcohol. 

 If they are prepared with the chrom-osmic mixture, their form is 

 perfectly preserved, but the transparency is partly lost. 



The Gymnosomata are placed in chloral hydrate solution of 0.1 of 1 

 per cent for from six to twelve hours and then are quickly killed with 

 acetic acid or sublimate. Good preparations of Gliopsis have been made 

 by letting the animals die in chromic acid of one-fourth of 1 per ceut. 



Cephalopoda. — The preparations are much better, of course, when 

 the animals are immersed in the preserving fluid while still alive. If 

 they have been dead for some time when received, they can be made to 

 regain their shape in part by allowing them to lie in sea water for 

 about an hour. Then they had better be hardened in 1 per cent 

 chromic acid for fifteen to sixty minutes, according to their size. 



Small octopods are narcotized in chloral hydrate of 0.2 of 1 per cent, 

 and then immersed in alcohol, where they sometimes contract, twisting 

 the arms about the body, but after the animals are dead it is easy to 

 stretch out the arms and dispose them in a natural position. The 

 larger animals (of a length of 15 cm. (6 inches) or more) are killed in 1 

 per cent chromic acid, where they are usually kept a half hour, though 

 very large ones may remain even so much as two hours. After wash- 

 ing them in fresh water, transfer to 70 per cent alcohol, taking care to 

 change the latter several times. 



Ocythce catenulata {PMlonexisa). — Females of medium size are im- 

 mersed directly in 70 per cent alcohol and after they are dead their 

 arms are straightened out. Scceurgus tetracirrhus (Octopus) is killed 

 in the mixture of alcohol and chromic acid and after twenty minutes is 

 transferred to alcohol. 



The Decapods may be put at once into alcohol of 70 per cent, taking 

 care, before they are quite dead, to pull out the two tentacular arms, 

 which usually have contracted. The small species should be narco- 

 tized in chloral hydrate of 0.2 of 1 per cent or in alcoholized sea water 

 before they are put into the alcohol. To facilitate the penetration of 



