ANIMALS OP THE PAST 



345 



from Figure 220. It must be remembered 

 that these are all quite different forms from 

 the corals living to-day. 



Crinoids. — Then there were the crinoids, 

 or sea lilies (Fig. 221), members of the star- 

 fish branch. Here, again, we have an ex- 

 ample of a group of prehistoric anirhals 

 some representatives of which are living 

 to-day, for a crinoid is sometimes dredged 

 from the sea even now. They were much 

 more abundant then than at present. 



Mollusks. — Numbers of the mollusks 

 existed all through the paleozoic era. They 

 were unlike the mollusks of to-day and were 



probably not edible. 



Fig. 221.— 

 Crinoid. 



Orthoceras. 



One of them, the 

 Orthoceras, possessed 

 a straight, tapering 

 shell, chambered like the shell of 

 the pearly nautilus (Fig. 222). In 

 fact, this animal belongs to the 

 same class as the nautilus and 

 squid. The Orthoceras varied from 

 a few inches to ten or twelve feet 

 in length. 



Insects. — In the early part of 

 the paleozoic era we find signs of 

 insect life, if we may call a scor- 

 pion an insect. More than this, 

 the scorpion is the first air-breath- 

 ing animal found in the rocks of 

 America (Fig. 223). Later on, in 



