Pteropoda. — The Hyaleidae 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 alcohol, and so on. Criseis acicula 

 is well prepared by killing it with alcoholized sea water. 



Cymbuliidae are very well killed in Perenyi's solution, 

 where they may remain fifteen minutes before they are trans- 

 ferred 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 pre- 

 parations of Cliopsis have been made by letting the animals 

 die in chromic acid of one-fourth of 1 per cent. 



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 minu- 

 tes, 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 some- 

 times 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 washing them in 

 fresh water, transfer to 70 per cent alcohol, taking care to 

 change the latter several times. 



Ocythoe catenulata (Philonexisa) . — Females of medium size 

 are immersed directly in 70 per cent alcohol and after they are 

 dead their arms are straightened out. Scaeurgus 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 narcotized 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 the alcohol into the 

 visceral region of the largest specimens an incision should be 

 made in the ventral part of the body. 



The transparent pelagic forms (Loligopsis, Verania) are 

 put first into Kleinenberg ' s solution and after an hour are 



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