[35] THE PRESERVATION OF MARINE ANIMALS HOVEY. 



As cocaine is not always available, tlie old methods for treating gas- 

 tropods will be detailed. It is to be understood that when cocaine is 

 used for narcotizing the subsequent treatment is that indicated below: 



The Placophora and the families of the Patellidte, the FissurellidaB, 

 and the Haliotidse may be prepared in a distended condition by narcotiz- 

 ing them with alcoholized sea water. 



Natica josephinia may be fixed in complete distention by dropping 70 

 per cent alcohol little by little into the sea water until the animals no 

 longer respond to any stimulus, an operation which often lasts two or 

 three days. Then they are killed by rapidly pouring concentrated 

 acetic acid over them, and they are transferred at once to weak alcohol. 

 If one desires to get i)erfect specimens he must treat several at once, 

 because out of every lot some are sure to remain more or less con- 

 tracted. 



Natica millepunctata and M. hebrea, when treated in the manner just 

 described, remain entirely contracted. Good results may be obtained, 

 however, by letting them remain for some days in a mixture of sea 

 water and fresh water in equal parts, and afterwards killing them with 

 acetic acid. This may be used for preparing several species of J^assa, 

 ColumheUa, Conns, and Trochus. 



Heteropoda. — The Atlautidse may be narcotized in alcoholized sea 

 water, where they are allowed to remain for from six to twelve hours, 

 and are then i^laced directly in alcohol. Cocaine, however, is much 

 better for narcotizing. 



The Pterotrachaidte are killed by immersing them in chrom-acetic 

 mixture ISTo. 1 for from ten to thirty minutes according to their size. 

 Wash thoroughly in fresh water and transfer gradually to the different 

 grades of alcohol. These animals are well prejiiired also with the 

 chrom-osmic mixture, and the little specimens of Carinaria are best 

 treated with the mixture of sulphate of copper and sublimate. Large 

 si)ecimeus should be suspended in the i^ermaneut receptacle by a thread 

 tied around the end of the proboscis. 



Opisthohranchiota. — The Bnllas are slowly narcotized in the mixture 

 of sea water and fresh water in equal parts or in alcoholized sea water 

 and allowed to remain therein until thoroughly insensible. They are 

 killed with concentrated acetic acid and transferred at once to alcohol. 



Gastropteron meckeli is killed in Kleinenberg's solution, thereby retain- 

 ing its natural red color very well. It loses its color in the ordinary 

 liquids. 



Doridium and Scaphander. — Narcotize in alcoholized sea water, kill in 

 concentrated acetic acid, and quickly transfer to alcohol. If not hard 

 enough, or if softened at all in the acetic acid, they may be placed in 

 chromic-acid solution of 1 per cent for ten or fifteen minutes before they 

 are x)ut into alcohol. 



PJiiline. — When the animal is well distended in a little sea water, sud- 

 denly pour over it concentrated acetic or pyroligneous acid and quickly 

 transfer to alcohol. 



