372 SOME ZOOLOGICAL METHODS. 



succeeds well with Dendrophyllia, Antipathes, Astroides, Clado- 

 cora, and Caryophyllia. 



For preparing sections, besides the usual methods for 

 sectioning decalcified specimens, we have the valuable methods 

 of von Koch and Ehrenbaum, 303 and 304, which, being 

 applicable to undecalcified specimens and furnishing prepara- 

 tions showing at one and the same time soft parts and hard 

 parts in situ, render most inestimable services. 



The Alcyonaria have also extremely contractile polyps. I 

 suggest for their fixation either hot sublimate solution, or 

 glacial acetic acid ( 51). GARBINI (Mamtale, p. 151) says 

 that the polyps may be fixed in the state of extension by 

 drenching them with ether, and then bringing them into 

 strong alcohol. 



WILSON (Mitth. Zool Stat. Neapel, 1884, p. 3) kills Alcyo- 

 naria with a mixture of 1 part of strong acetic acid and 2 

 parts of concentrated solution of corrosive sublimate, the 

 animals being removed as soon as dead and hardened for two 

 or three hours in concentrated sublimate solution. 



SCHULTZE (Biol. Centralb., 1887, p, 760) says that for Penna- 

 tulida with large polyps the gradual addition of fresh water is 

 a good plan. 



BRAUN (Zool. Anz., 1886, p. 458) recommends that for both 

 Zoantharia and Alcyonaria a little osmic acid be added to the 

 sublimate employed for fixation. For Alconium palmatum, 

 Sympodium coraHoidea, Gorgonia verrucosa, Caryophyllia cya- 

 thus, and Palythoa axinellse he proceeds as follows : The 

 animals are left for a day or two in a glass vessel, so that the 

 polyps may become thoroughly extended. They are then 

 suddenly drenched with a mixture of 20 to 25 c.c. of concen- 

 trated solution of sublimate in sea- water with four to five drops 

 of 1 per cent, osmic acid. This is allowed to act for five 

 minutes. 



(This method also gives good results with Hydra and some 

 Bryozoa and Rotifers.) 



742. Anthozoa : Maceration. The HERTWIGS (Jen. Zeitschr., 

 1879, p. 457) treat the tissues of Actinias for two or tlnvr 

 minutes with a mixture of : 



0'04 per cent, osmic acid in sea- water . 1 part. 



0*2 per cent, acetic acid . . . 1 



