THE PERIWINKLE. 59 
subulate tentacle, aud just below each tentacle is a 
short peduncle, quite free from the tentacle, carrying 
an eye at its apex ; between the tentacles are a pair 
of lobes. Behind the tentacles, along the upper side 
of the foot, there is a fold of the mantle, bearing on 
its margin three tapering filaments on each side. 
4. Break the shell with a hammer, and extract the 
animal. Notice that it is attached to the columella 
by a short thick white muscle—the columellar 
muscle. Put the animal in a tumbler with weak 
vinegar and water. Let it remain for two or three 
hours. Then put it in spirits, 20 over proof, for an 
hour, to coagulate the mucus. 
o. Fasten the animal to the loaded cork, dorsal side up, 
by two pins through the foot, one on each side of 
the head. Cover with water. Notice the cavity 
formed by the mantle forming a kind of hood over 
the head, completely open in front. Cut open this 
mantle cavity along the right side, from before back- 
ward, and turn the flap over to the left. Notice on 
the flap of the mantle thus turned over, the brown 
branchia, or gill, free at the tip; the second or left 
branchia is rudimentary. Outside the branchia lies 
a white organ—the renal organ—and outside that, 
the brown or whitish (according to its contents) 
rectum ending in a free anus. At the base of the 
branchia lies the heart. It is white, and composed of 
an auricle and a ventricle, the auricle receiving the 
blood from the branchia. 
6. Open the spiral portion of the animal. Notice the 
large saccular stomach, surrounded by the olive- 
brown liver, and the pinkish white, or yellowish, re- 
productive gland. These two, so closely united 
