64 Practical Zoology. 



Topics for Reports. The Oyster Industry. The Pearl Fisher- 

 ies. Pearls from Fresh-water Clams. Kitchen Middens. Clam- 

 bakes. Wampum. Tridacna. Mother-of-pearl. Pearl Button 

 Factories. The Chambered Nautilus. The Paper Nautilus. The 

 Giant Squid. The Octopus. Snails as Food. 



THE POND SNAIL. 



A dipper with a perforated bottom, attached to a wooden 

 handle, will be found convenient in scooping up the sand and 

 mud from the bottoms of ditches and streams; the dirt being 

 washed out, the shells and other objects will be left behind. Get 

 a number of live snails, and keep them in a fruit jar. 



1. The broad disk on which the snail creeps is the foot. 



2. The "horns" are the feelers, or tentacles; touch them; 

 what would seem to be their use ? 



3. The dark spots at the bases of the tentacles are the eyes ; 

 are they borne on a stalk in any common snails? 



4. Watch the snail crawling on the glass ; near the front of the 

 foot the mouth may be seen ; observe its opening and shutting as 

 the snail gathers food from the surface of the glass. Do snails 

 clean the glass or foul it? Most snails have a ribbonlike tongue, 

 fastened at each end, and covered with teeth ; as this tongue is 

 applied to an object, and drawn rapidly back and forth, it acts like 

 a rasp. 



5. Watch the snails, to see if any of them come to the surface 

 to get air ; how is this done? 



6. Collect also land snails and river snails. Keep them and 

 watch them to learn their structure and habits. 



THE SNAIL SHELL. 



1. The pointed end is the apex. 



2. The opening at the large end is the aperture. 



3. The outer edge of the aperture is the lip. 



4. The lines parallel to the lip are the lines of growth. 



5. The spiral groove on the outside is the suture. 



