242 NEW YORK STATE MUSEUM 



pose of a successful dissection. lu drowning tlie animal, I have 

 need a fruit-preserving jar, as being more convenient than a wide- 

 mouthed bottle. The jar should be completely filled with water, 

 so that, when the cover is fastened on, there will be no air space 

 left. The animals being placed in the water and the cover 

 screwed on, the jar should be left undisturbed for 48 hours; it 

 requiring about that length of time to drown the animals. Ke- 

 maining undisturbed, they will die fully extended; but, if the jar 

 is disturbed in the meantime, more or less contraction vdll take 

 place. The animal when dead should be thoroughly washed to 

 free it from all adhering mucus, and placed in alcohol diluted 

 with about two thirds the amount of water, additional alcohol 

 being added from day to day till the mixture consists of about 75^ 

 of alcohol. The animals should then be removed and placed in 

 undiluted alcohol, when they will keep indefinitely. If placed at 

 once in strong alcohol, the action of the fluid on the integument 

 prevents the proper preservation of the internal organs. 



To remove the shell, preparatory to dissecting the animal, 

 break the peristome with a small pair of pliers. The remainder 

 of the shell can be removed with a pair of forceps, carefully break- 

 ing off a small piece of shell at a time till it is removed to the 

 apex. The columella can be removed by holding the lower part 

 between the thumb and forefinger of the left hand, and turning 

 the animal with the right. As the columella is like a screw, the 

 animal readily becomes detached by this movement. 



In dissecting the animal, a circular china dish about 4 inches 

 in diameter and 2 in depth will be necessary; also a piece of sheet 

 cork as large as will lie at the bottom of the dish, fastened to a 

 thin sheet of lead with either string or rubber bands. It is best 

 to have the lead of the same size as the cork. This leaded cork 

 is to be placed in the bottom of the dish, and the dish filled with 

 alcohol. If the animal has once been placed in alcohol, all dissec- 

 tions should be made in alcohol, but freshly killed specimens may 

 be dissected in water, and many of the organs at this time present 

 a much more natural appearance than when acted on by alcohol. 

 Place the animal on the cork and fasten it down with small pins, 



