BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [26 { 



The preparation succeeds much better in a very high cylinder, on 

 account of the great extensibility of the nettle-filaments. When the 

 colony is well distended pour over it a volume of the sublimate and 

 acetic acid mixture equal to one-fourth that of the sea water contain- 

 ing it. As soon as dead, the colony should be transferred in the same 

 manner as at first to a similar cylinder containiug chromic acid of one- 

 half of 1 per cent and after twenty minutes to 50 per cent alcohol, and 

 finally to that of 70 per cent. 



HippopodiuSj Galeolaria, and Ahyla. — Kill with the mixture of sul- 

 phate of copper and sublimate and put directly into weak alcohol. 

 The bell oi Ahyla is also well prepared with the chrom-osmic liquid. 



Praya is fixed like Hippopodiiis, but is hardened in the mixture of 

 potassium bichromate and osmic acid, where it may remain one or two 

 days. 



Diphyes. — Use hot sublimate for killing, with the chain of the individ- 

 uals distended. 



Velella is killed with the chrom-picric mixture, or with that of sub- 

 limate and chromic acid, and after a few minutes is removed to weak 

 alcohol. 



Porpita is slowly killed by dropping with a pipette a few drops of 

 Kleinenberg's solution into the beaker where it has become distended. 

 When the beautiful blue color of the colony has begun to turn red is 

 an effect of the acid, it should be removed to the Kleinenberg solution, 

 where it may remain fifteen minutes before it is put into weak alcohol. 



CTENOPIIOKA. 



Beroe ovata, Horniiphora, CalUanira, Lampetia, PJiichlora, and young 

 specimens of Gestiis, Uueharis, and Bolina are killed in the chrom-osmic 

 mixture, in which they remain from fifteen to sixty minutes, according 

 to size, and are then transferred gradually to 70 per cent alcohol. 



While Beroe ovata is hardening in the alcohol, insert a short glass 

 tube of the proper size into its gastric cavity to keep it distended in 

 natural shape. Fix the tube so that it acts like a float to keep the 

 animal suspended in the liquid. This operation must be effected with 

 great care to avoid injuring the longitudinal series of vibratile plates. 

 After one or two days, when the animal is in the 70 per cent alcohol, 

 the tube may be removed and the hardened animal will preserve its 

 form. 



Beroe forshalii^ to be preserved in a state of expansion, must be 

 immersed in the sulphate of copper and sublimate mixture, and as soon 

 as dead must be placed in the chrom-osmic mixture to harden for an 

 hour. Since this species is naturally flat, it is not necessary to intro- 

 duce a tube into it. 



Callianira may be treated like the last species, but another good 

 method is to kill it in a solution comj)osed of — 



Concentrated pyroligneoua acid 1 part. 



Saturated sublimate 2 parts. 



Chromic acid of one-half per cent 1 part. 



