148 



LIFE BY THE SEASHORE. 



(3) The Echinoids, or Sea-Urchins. Body more or less rounded, 

 covered by spines, test composed of plates arranged in regular rows. 



/Test well rounded, 

 Body spherical, anus spines pinkish or 



opposite mouth, five 



regular double rows 

 of ambulacral plates, 

 Aristotle's lantern 

 present . 



Body heart - shaped, 

 anus posterior, am-^ 

 bulacral areas peta- 

 loid, no lantern 



Echinus 



white E. escu- 

 lentus. 



Test depressed, spines 

 purple-tipped E. 

 miliaris. 



c, . , ,, f [ Colour golden when 



Spines and therefore fresh * nteriortube _ 



tubercles,nearlyequalj f | n ft ye ._ 



-Echmocardium 



Some spines, and there- 



K Colour purple S. 

 purpureus. 



fore some tubercles, 

 larger than rest 

 Spatangus . . - 



(4) The Holothurians, or Sea-Cucumbers. Body more or less 

 elongated, without well-developed skeleton. Mouth with a fringe of 

 tentacles. 



Tube - feetfTentacles ton, 



present . ^ edCucumana . . 



JTentacleswithsimplelateran T d t d 

 Tube - feet! branchesordigits, anchors ' 



absent .| and^hor-plates present 



, 



