POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 243 



or^ better yet, with very fine, short needles, inserted through the 

 margin of the foot. Then, with the fine pair of scissors, com- 

 mencing at the head, cut through the integument along the center 

 of the back, taking care not to injure any of the organs below. 

 The integument is now to be removed from the dorsal part, 

 turned back and fastened to the cork^ removing the needles from 

 the margin of the foot and putting them through the edges of the 

 integument. All the organs of the anterior part of the snail are 

 thus brought into view, and farther dissection of the organs can 

 be intelligently made. 



In the case of the L i m a x nearly all the organs will be 

 brought into view by turning back the integument; but great 

 care must be taken in this genus in cutting through the integu- 

 ment not to injure the pulmonary chamber, as it is situated very 

 near the surface. Also every precaution should be taken that 

 the points of the scissors shall not go below the integument, or 

 the intestine and upper surface of the stomach will be mutilated, 

 and a successful dissection rendered impossible. 



Habits 



Polygyra albolabris. The snails of this species are found in 

 woods near fields, in ravines and in other situations. They re- 

 main concealed through the day when the sun is shining, coming 

 forth for their food toward evening and after showers. It is at 

 these times that they are most easily found during summer. Fre- 

 quently they may be found on the under side of boards, logs and 

 stones. During cold weather they hibernate, partially burying 

 themselves in the ground, with the apex of the shell downward. 

 At this time they are very easily found by scraping away the 

 dead leaves so as to expose the surface of the ground. While 

 hibernating the animal is completely withdrawn in the shell, the 

 mouth of which is closed by a mucous excretion, which becomes 

 hardened on exposure to the air. It is stated by nearly all 

 writers on this subject that there is always a perforation in this 

 membrane to allow the passage of air; but I have observed 

 numerous cases where the membrane was entire. 



