120 THE SNAIL. 



is a large round hole, the respiratory aper- 

 ture, leading into the pulmonary chamber. 



Wash away the mucus from the collar on the right side ; 

 clean the notch in the collar, and pass a seeker through the 

 respiratory aperture into the pulmonary chamber. 



iv. The anus is a smaller slit-like hole, immediately 

 below and to the right of the respiratory 

 aperture. From it a spout-like groove runs 

 forwards to the edge of the collar. 



Clean the anal opening and groove, and pass a seeker into 

 the anus and back along the rectum. 



v. The aperture of the pedal mucous gland is 



immediately below the inferior lip, between 

 the head and the foot. 



Pass a seeker into the aperture, and backwards along the 

 gland, and lay the gland open along its whole length. 



B. After Removal of the Shell. 



Twist the animal out of the shell, taking care not to damage 

 the upper part of the body in so doing. The shell comes off readily 

 if the snail has been put into spirit for a short time after drowning. 



1. The Shell. 



a. The colour differs a good deal in different speci- 



mens. The ground colour is a yellowish brown, 

 marked by darker longitudinal bands running 

 round the spiral, and by obliquely transverse 

 lines corresponding to the lines of growth. 



b. The nucleus is the oldest part of the shell, at the 



top of the spiral, corresponding to the umbo of 

 the mussel-shell. 



c. The mouth is oval, and notched posteriorly by the 



penultimate turn of the shell. Its lip is smooth 

 and slightly everted. 



