Survey of the Animal Kingdom 305 



Fig. 110. — Sand dollar {Echinarachnius parma) oi th.& -phylnva Echinodermata, 

 class Echinoidea. Upper view shows aboral surface; lower, the oral surface. In 

 the aboral view, the darker ambulacral areas, or "petals," are shown. In the oral 

 view, the ambulacral areas are shown as narrow furrows radiating from the 

 central mouth. (From Coe: Echinoderms of Connecticut, State Geological and 

 Natural History Survey of Connecticut, Bulletin 19.) 



