New York State Museum 



POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 



INTRODUCTION 

 Methods and apparatus 



Specimens of Polygyra and L i m a x may be easily kept 

 in captivity by placing them in d box in which there are about 4 

 inches of earth covered with dead leaves. The earth must be 

 kept moist. The box must be covered with mosquito netting or 

 tarlatan. The mosquito netting will be sufficient for adult indi- 

 viduals, but the young of L i m a x would escape easily through 

 its meshes. 



For the study of the histology and embryology a compound 

 microscope is necessary, with 2 inch, f inch and ^ inch objec- 

 tives. A dissecting microscope is almost indispensable. I have 

 used, for that purpose, one manufactured by Bausch & Lomb of 

 Rochester (N. Y.), known as the " laboratory dissecting micro- 

 scope," fitted with a Hastings aplanatic lens. A cut of this in- 

 strument is given herewith. Two pairs of fine scissors will be 

 necessary, one pair with straight points, the other with curved 

 points; one or more fine scalpels, and two pairs of fine forceps, 

 one straight and the other curved. A pair of stronger forceps and 

 a pair of fine pliers will be needed to remove the shell of 

 Polygyra. Dissecting needles are also necessary. These 

 can be made by forcing the heads of fine needles, by means of 

 a pair of pliers, into the end of a round stick of small diameter. 

 The point of one of these needles should be bent so as to form 

 a hook, first heating the end of the needle to a white heat. 



Methods of killing and manipulating 



I have tried all of the various methods recommended for 

 killing Polygyra and L i m a x , and find only one that is 

 uniformly successful, and that is drowning. In using hot water 

 and various chemicals, in nearly every case the animal is 

 more or less contracted, and thus rendered useless for the pur- 



