68 



COELENTERATA AND 



Apical area with irregular plates. Pluteus without anal 

 rods. 



S. Drobachiensis. 

 Clypeaslroids. 

 Echinarachnius. Body nearly circular, very flat with 

 sharp, entire margin. Vent close to edge. Petaloid re- 



^#•3^ ^ 





ECHINARACHNIUS. 



gion marked. Spines small, short, brown or reddish color. 

 Pluteus without anal rods. 



E. parma. 

 /Spalangoids. 



Schizaster. Body heart-shaped, irregular, oval with 

 avenues on the upper surface. Mouth asymmetrical. Test 

 thin, fragile. Ambulacral zones depressed and petaloid. 

 Pluteus with single median calcareous rod on the anal lobe. 



S. frag ills. 



