430 



NATURE STUDY AND LIFE 



soft-bodied animals without segments and without jointed 

 limbs. Generally the body is protected by a shell, either 

 single and coiled spirally, as with snails, periwinkles, and 

 conchs, or composed of two pieces or valves, as in clams, 

 oysters, and mussels. A few have no shell, as the garden 

 slugs and the most highly developed of the whole group, 

 the octopus and ink squid. 



While the children may be encouraged to collect fossil 



Fig. 174. Type Forms of Mollusks 

 a, fresh-water clam; b, pond snails; c, garden slug; d, octopus. 



shells and the many species that they may find during 

 their summer vacations at the seashore, we will confine 

 our attention to four of the commonest and most widely 

 distributed kinds. 



Can some boy or girl bring in two or three specimens of 

 the common garden slug, with a nest of eggs, if they can 

 be found .' They may be kept in a small aquarium and 

 fed on lettuce leaves or fresh young radishes to show what 



