50 TAXIDERMY AND MODELLING 



acetic, and picric acids, bichloride of mercury, and with cortimon 

 or distilled water, rarely with sea-water, and is not recom- 

 mended to be used with alcohol for many reasons. 



Such sponges as the Halisarcidae are fixed extended if left 

 for half an hour in a i per cent, solution, which is used also as 

 a secondary or hardening fluid. 



The "sea-grapes" — egg clusters of such Cephalopoda as 

 Sepia — are fixed in a |- per cent, solution, and in the course 

 of an hour removed to weak alcohol, brought up gradually to 

 70 per cent.; but those which are contained in one common 

 gelatinous envelope, after fixation by the acid, are placed de- 

 finitively in 50 per cent, alcohol. 



37. — Chromic and Acetic Acids (No. i) (Lo Bianco, p. 443) 



Chromic acid (i per cent.) . . .100 parts 



Acetic acLd (concentrated) . . . 5 » 



Ascidians, such as the chains of young, and solitary forms, 

 of Salpa maxima and 5". pinnata, chains of young forms of 

 6". bicaudata, the two adult forms of S. fusiformis and demo- 

 cratica-mucronata . are fixed by the above for ten minutes, and 

 then passed directly into weak alcohol, brought up gradually 

 to 70 per cent. 



38. — Chromic and Acetic Acids (No. 2) (Lo Bianco, p. 443) 



Acetic acid (concentrated) . . .100 parts 



Chromic acid ( I per cent.) . . . 10 „ 



Some of the Alcyonaria are fixed by plunging them rapidly 

 into the above, and suspending them as soon as dead in a 

 preparation - jar containing weak alcohol, in such a manner 

 that the polyps do not touch the sides ; and if the polyps 

 remain well extended, their transference into stronger alcohols, 

 until 70 per cent, is reached, is made gradually. If, however, 

 bubbles of air form in the weak alcohol and adhere to the 



