CHAPTER XLV 

 METHODS FOR VARIOUS INVERTEBRATES 



1166. Recent methods for various invertebrates consist 

 largely in the application of the techniques given in Chapter XXX, 

 § 679 to § 738. This applies especially to such organisms as 

 sponges, small cha^topods, tunicates, coelenterates, etc., and 

 larvae. Improvements in imbedding and cutting will be found 

 in § 124 to § 222. These will be of special assistance with 

 arthropods. 



1167. Tunicata. A method of Lo Bianco * for killing simple 

 Ascidians in an extended state has been given, § 24. Some 

 forms, such as Clavellina, Perophora, Phallusia, Molgula, Cynthia, 

 etc., should first be narcotised by treatment for from three to 

 twelve hours with chloral hydrate (1 : 1000 in sea-water), then 

 killed in a mixture containing chromic acid of 1 per cent. 10 parts, 

 acetic acid of 50 per cent. 100 parts, and finally hardened in 1 per 

 cent, chromic acid. 



The compovmd Ascidians with contractile zooids may be left 

 in clean sea-water till the zooids have become fully extended, 

 then fixed by van Beneden's acetic acid process, § 89 (steel 

 instruments being avoided for manipulating them). We strongly 

 recommend this process, 



S. Lo Bianco recommends for this group the chloral hydrate 

 process, followed by fixation with sublimate or chromo-acetic 

 acid. 



Caullery (Bull. Sc. France Belg., xxvii, 1895, p. 5) first stupefies the 

 animals with cocaine (Laiiille, a few drops of 5 per cent, solution to 

 30 c.c. of sea-water), then fixes in liquid of Fleniming or acetic acid. 



Most small pelagic Tunicates are very easily fixed with osmic 

 acid or acid sublimate solution. 



Lee foimd the acetic acid process very good for Pyrosoma. 

 Lo Bianco puts them for a quarter of an hour into 50 per cent, 

 alcohol containing 5 per cent, of hydrochloric acid, then into 

 successive alcohols, beginning with 60 per cent. He kills the 

 hard forms of Salpa with acetic acid of 10 per cent., the semi- 

 hard ones with 1 per cent, chromic acid containing 5 per cent, 

 acetic acid, the soft ones with 1 per cent, chromic acid containing 

 /^ per cent, osmic acid, or 10 parts of 1 per cent, chromic acid, 



* References to methods of Lo Bianco in this chapter are all to his 

 paper in Mitth. Zool. Stat. Neapel, ix, 1890, p. 435. 



590 



