BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [24] 



receptacle, makiug it necessary to change the alcohol frequently and to 

 add a few drops of concentrated sulphuric acid thereto. 



The larval forms of the Acalephs {ScypMstoma, Strobila) are killed 

 with hot saturated sublimate. Strohila is also well iixed with a mix- 

 ture consisting of 9 parts of concentrated acetic acid and 1 part of 

 osmic acid of 1 per cent. From this it is quickly transferred to fresh 

 water for washing and put into alcohol. 



SIPHONOPHORA. 



As with the Hydromedusse, the preparation of the Siphonophora 

 should be accomplished as soon as possible after crapture, and only 

 those specimens should be treated which are in good living condition. 

 Particularly with the Physophoridse is it true that the whole colony 

 will go to pieces if it remains for a few hours in the same receptacle in 

 which the water has had a sudden change of temperature, though fre- 

 quently the breaking up does not take place until the colony comes in 

 contact with the fixing fluid. Much care must also be exercised not to 

 shake roughly the vessel which contains the animals before they have 

 been killed. It has often been observed that a trace of an acid or other 

 reagent in the water is enough to destroy the colony. The receiving 

 vessel must be perfectly clean. 



Athoryhia rosacea^ the single representative of the family of Athory- 

 biadae, which is found in the Bay of Naples, is very rare, and but one 

 specimen has been prepared at the station. That was killed with the 

 mixture of sulphate of copper and sublimate. The colony contracted 

 somewhat, but remained entire. It was washed with fresh water and 

 then placed in alcohol. 



The very delicate ^Yietdie^ [Physophoridce, Agalmidce) vaxx^t be trans- 

 ferred from the jar in which they were captured to the crystallizing 

 dish in which they are to be killed by immersing both vessels in a tank 

 of water and cautiously pouring the animals over. Leave water enough 

 in the crystallizing dish to give the colony free movement, and wait for 

 the i^olyps and the nettle-filaments to become well distended and 

 naturally arranged before going on with the treatment. 



Physophora, A()alma, HaUstemma, and Forskalia are killed with the 

 mixture of sulphate of copper and sublimate in volume equal to or 

 double that of the water in the crystallizing dish containing then). The 

 mixture must be poured rapidly into the dish and not directly onto the 

 animal. After a few minutes, as soon as dead, the colony should be 

 transferred by means of a large horn spatula to the hardening solution, 

 which is not the same for all the species. 



{a) Physophora, Agalma, and HaUstemma are put directly into 35 per 

 cent alcohol, and after a few hours transferred to that of 70 per cent. As 

 soon as Physophora has been put into the 35 per cent alcohol, its nettle- 

 filaments should be stretched out as far as possible with a j)air of light 

 forceps before they become rigid. To change the liquid in the swim- 

 ming bell it is necessary to make an injection with a pipette. Bubbles 



