and perhaps better way of handling these forms is to allow them 

 to expand in a specimen tube less than half full of water, and 

 when they are well distended to fill the tube with acetic acid. 

 Transfer them at once by pouring into the tube containing the 

 mixture of alcohol and chromic acid. A few minutes later pour 

 out a small portion of the liquid in the tube and add chromic 

 acid, because considerable water will have gone over with the 

 animals. After fifteen minutes wash in fresh water and transfer 

 to 35 per cent alcohol. Still another method is to use the chrom- 

 osmic acid mixture as a hardening medium, but the animals do not 

 remain as transparent and the tentacles are somewhat contracted. 



During the hardening process, especially when many of the 

 medusae are treated at the same time, the tube should be held in 

 a horizontal position in such a way that the bells are down on 

 the side of the tube and the animals not in contact. For the 

 final preservation of certain forms (like Lizzia) place them in 

 alcohol in a small tube, separating the individuals by wads of 

 cotton, and put this into the exhibition jar. 



Oceania conica and Tiara pileata are narcotized in alcohol- 

 ized sea water (3 per cent) and then treated like the preceding. 



Medusa Forms Of The Campanularidae 



Eucope, Gastroblasta, and Obelia are fixed in the mixture 

 of sulphate of copper and sublimate and after a few minutes are 

 washed in fresh water until every trace of precipitate has vanish- 

 ed, and then placed in weak alcohol, and so on. 



Mitrocoma and AEquorea are killed with acetic acid and 

 immediately transferred to the chrom-osmic mixture, where they 

 may lie from fifteen to thirty minutes, according to their size. 

 Small specimens of AEquorea can be placed at first in the chrom- 

 osmic mixture. 



Tima flavilabris is best preserved by killing in formalin 

 of 4 per cent, where it may remain from five to twenty days, if 

 desired, before the transfer to alcohol begins. This transfer 

 must be made very gradually. The older method of treatment is to 

 kill the animal with chromic acid of 5 per cent in volume equal- 

 ing that of the water in which it is, and after five minutes to 

 transfer it to the chrom-osmic mixture. After half an hour in 

 the latter mixture wash in fresh water and transfer to alcohol. 

 This method stains the animal brown, while that with formalin 

 leaves it colorless. 



Olindias iruilleri. — The old method is to kill with acetic 

 acid and immediately transfer to chromic acid of 1 per cent, where 

 the marginal tentacles are to be stretched out by means of a pair 

 of forceps, and where the animals may remain about a quarter of 

 an hour before they are removed to the weak alcohol. The new 



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