the fluid contained therein. After immersion in alcohol one must 

 see that the liquid fills the internal cavity, and, on changing 

 the animal to stronger alcohol, that the liquid contained within 

 the shell is changed also. 



If dry specimens of echini are wished, discharge the 

 water within the shells and let the animals lie in ordinary 70 

 per cent alcohol for one or two days before placing them in the 

 wind and sun to dry. Starfish also make better dried specimens 

 if they are killed in 70 per cent alcohol and allowed to remain 

 there two or three days before they are dried. 



Holothurioidea. — Holothurians require more care than other 

 echinoderms, because they have soft and very contractile bodies 

 and all are furnished with tentacles which contract or retire 

 within the body on contact with a reagent. Some species, further- 

 more, soon after they are immersed in the fixing fluid expel their 

 viscera and become valueless as specimens — a thing which may 

 happen in the sea water also, if that is changed too suddenly. 

 All these inconveniences are avoided by treating the animals by 

 the methods here described. 



First of all, as with other animals which must become ex- 

 panded, they are placed in clear sea water. Those species which 

 are killed in acids should be allowed to remain in them only just 

 long enough to cause death, so that the calcareons cutaneous 

 spicules be not injured. Large specimens of Holothuria and 

 Stichopus as soon as the tentacles are fully distended should be 

 seized with two fingers or with a pair of forceps, a little be- 

 low the tentacles, lifted from the sea water and be immersed as 

 to the anterior portion only in a rather deep vessel containing 

 concentrated acetic acid. At the same time another person should 

 inject some 90 per cent alcohol into the animal through the anal 

 aperture with a syringe, taking care not to exert too great press- 

 ure, lest the body be distended too much. Before the Holothurian 

 is quite dead it is to be immersed in 70 per cent alcohol, closing 

 the anal orifice with a small cork to prevent the excape of the 

 liquid and the consequent flattening of the body. The injection 

 should be repeated at each successive renewal of the alcohol. 



With certain species, as, for example, Holothuria poli, the 

 operations must be performed with much caution, because the skin 

 is easily injured. 



H. impatiens, which has a long, soft body, is to be seized 

 by the neck, so that the tentacles can not contract, and by the 

 posterior extremity, so that the body may not shorten, and in this 

 manner the whole animal is immersed in concentrated acetic acid. 

 When dead it is transferred at once to alcohol, without making an 

 injection. 



Thyone, Thyonidium, and Phyllorus are strangled without 

 using much force, wholly immersed in acetic acid, and then removed 



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