[NHCOLL-L:4473] RE: Choosing a preservative for cnidarians

[Moore, Simon]

I used to work in the Natural History Museum's (London) cnidarian
collection in the 80s and my mission was to upgrade its level of
preservation.
 
The basic rules are/were: if it's a medusoid (siphonophora,
chondrophora, scyphozoa, cubozoa and stauromedusae and all hydromedusan
groups) plus the more delcicate athecate hydroids [Corymorpha] which
don't have much 'exoskeleton' - these must be formalin fixed and stored
in an aqueous preservative such as 5% formalin (half fixation strength),
Steedman's fixative (contains same amount of formalin).  The glycol
groups of preservatives cause too much swelling for long-term 'safe'
preservation.
Thecate hydroids, all anthozoans, hydrocorals should be formalin fixed
and then taken through an alcohol ladder to an alcohol preservative,
although I tried isopropyl alcohol but found it too embrittling.
Colourful actiniarians were put through the Kaiserling 'system' and
still show some of their colour after nearly 30 years.  I also wrote a
paper; 

 MOORE, S. J. - 1989b: Narcotising sea anemones. Journal of marine
biological Association of United Kingdom, 69 (4): 803-811.

MOORE, S. J. - 1997a: Narcotising sea anemones. Natural Sciences
Conservation Group Newsletter, 5: 10-20.

The latter is also available via the NatSCA website, about
anaesthetising actiniarians prior to fixation.  Let me know if you would
like a copy.
Putting medusoids into alcohol (post fixation) is OK but the alcohol
will spoil the apperance by making them totally opaque and the canal
system in the hydromedusae, particularly, is much harder to see.  
ET Browne used to fix hydromedusae (c.1890) in 4% Osmic acid (an EM
fixative) and then transfer to alcohol and although the Osmium forms a
black heavy metal 'stain' for all the canal systems but bearing in mind
that his specimens are over 100 years old, they are in very good
condition, much better than any that were fixed in Bouin, formalin and
(I think) Zenker or Helly's fluids.  

1990: Investigation into the preservation of the E. T. Browne collection
of hydromedusae.  Journal of marine biological Association of United
Kingdom, 70; 477-480, (Reprinted 1994: Conservation News 53: 40-41.)

 

Let me know if any more specific info. is required.
 

With all good wishes, 
Simon Moore, MIScT, FLS, ACR, 
Senior Conservator of Natural Sciences. 
Hampshire County Council, 
Department of Culture, Communities and Rural Affairs, 
Museums & Archives Service, 
Chilcomb House, Chilcomb Lane, 
Winchester SO23 8RD. UK. 
Internal  8 327 6737 
01962 826737 
http://www.hants.gov.uk/museum/biology 


 

________________________________

From: owner-nhcoll-l at lists.yale.edu
[mailto:owner-nhcoll-l at lists.yale.edu] On Behalf Of Frederick, Moretta
RBCM:EX
Sent: 26 August 2009 22:15
To: NHCOLL-L at lists.yale.edu
Subject: [NHCOLL-L:4469] Choosing a preservative for cnidarians



I'm interested in hearing people's opinions regarding the best way to
preserve cnidarians.  

Specifically, I am interested in longterm storage in Formalin vs.
Formalin-fixed then transferred to isopropanol/ethanol vs. fixing and
preserving in isopropanol/ethanol (no formalin).  I am currently most
interested in this information as it applies to the Hydrozoa and
particularily hyroid colonies but would also be interested to hear how
others are storing all cnidarian groups. 

Thanks in advance! 

Moretta Frederick 
Collections Manager, Invertebrates, Fish, 
Reptiles, and Amphibians 
Royal British Columbia Museum 
ph.(250) 387-2932 
fax (250) 387-0534 


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