CHAPTEB XXXVI. 



Mi. I HubS FOB JNVEliTEBRAI 



Tunicata. 



852. Fixation of Tunicata. A method of Lo BIAMO* for 

 killing simple Ascidians in an extended state has, been given, 

 25. Some forms, such as Clavellina, Ptrophora , I'lmH- 

 Molyula, Cynthia, etc., should first be narcotised by treat- 

 ment 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 -V) per 

 cent. 100 parts, and finally hardened in 1 per cent, chromic 

 acid. 



The compound Ascidians with contractile zooids may be 1* ft 

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

 then fixed by VAN BKNKDKN'S acetic acid process, 84 (- 

 instruments being avoided for manipulating them). I 

 recommend this process. 



S. Lo BIANCO recommends for this group tin: 

 hydrate process, followed by fixation with sub! i mat < 

 chromo-acetic acid. 



CAULLEBY (Bull. 8c. France Bely., xxvii, 1895, p. 5) first stupefies the 

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

 30 c.c. of sea water;, then fixes in liquid of Fleiuming or acetic acid. 



Moat small pelagic Tunicates are very easily fixed with 

 nsmic acid or acid sublimate solution. 



I have found the acetic acid process very good for I'yrn- 

 oma. Lo BIAM:O puts them for a quarter of an hour into 

 ."iO per rent, alcohol containing 5 per cent, of hydrochloric 

 acid, th-n into successive alcohols, beginning with 60 per 

 (nt. He kills the hard form- of >V/ ////. with ;icefic acid of 

 10 per cent., the semi-hard ones with 1 per cent, chromic 



* References to methods of Lo BIANCO in thin Chapter are all to hi* 

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



