snail's shell was turned over or reflected, forming the peristome, and 

 was not thin and sharp, as was that of the pond snail. Professor 

 Parker said that in some land shells the lip was thin and sharp, 

 without a reflected peristome. We also noticed the white deposit 

 of shelly matter which covered the umbilicus. The Professor told us 

 that this showed that the snail was fully grown, as in the young snail 

 the umbilicus was very wide and deep. In some land snails, he said, 

 the umbilicus is always open, even in 

 adult life. On the inner lip, or parietal 

 wall, we noticed a small denticle, or 



tooth ami ( i flip nntsidp WP nhsprvprl Limax agrestis, a snail without an 



[e > ^ V e external shell. (Binney.) 



the fine, regular lines of growth. 



Professor Parker remarked that, as in the fresh- water snail, the shell 

 of the land snail was inseparably attached to the animal. But just 

 as he spoke several peculiar animals crawled along the log which we 

 had overturned, looking exactly like the snail without its house, and 

 George at once said, " Why, what are these ? Have they not lost their 

 shells ? ' The Professor replied that these were garden slugs, which were 

 snails that had no shell, but in its place, a tiny shelly plate situated 

 on the back to protect the lung, and covered by a part of the mantle. 



He then suggested that we watch the white-lipped snail and see 

 if it would crawl about. Soon we saw a slight movement, then the 

 large, fleshy foot appeared, and then the head was cautiously thrust 



out. A moment of hesi- 

 tation followed, the ten- 

 tacles and the rest of the 

 head appeared, and the ani- 

 mal stretched out and be- 

 gan to crawl over the log, 

 carrying the shell as shown 

 in the accompanying figure. 



White-lipped snail, showing parts of animal, e, eye; -A-S the animal crawled 

 ep, eye-peduncles; f, foot; h, head; n, neck; sh, part n l micr if ]pff ., o-li 

 of shell occuied b lun t tentacles. Binne. n &> 



ep 



of shell occupied by lung; t, tentacles. (Binney.) 



track of mucus behind it. 



From the head, two long tentacles extended which pointed straight 

 ahead. They moved about restlessly, touching every object which 

 came in the path of the animal, and retracting suddenly if any obstruc- 

 tion was met. These were the eye peduncles, and by looking very 

 closely, we could see the little black eyes at their tips. 



Harry gently touched one of the eyes with his finger to see what 

 would happen. It at once disappeared. Professor Parker asked us 



27 



