72 



THE STARFISH FAMILY 



which extend five arms or rays. On the disk is a porous 

 circular plate. It is known as the madreporic plate 

 (mad-re-por'ik : Greek, mater, mother ; poros, soft). It 





3 





Tfu 1 



Figure 72. — Diagram of Body of Starfish. 



c, liver ; v, stomach ; o mouth ; g , reproductive glands ; p, tube 



feet ; s, stone canal. 



serves to take water into a series of vessels by means of 

 which the animal moves and holds on to rocks and shells 

 at the sea bottom 



58. Internal Structure. — If the upper portion of the 

 animal is removed carefully, the internal structure can 

 be examined. Each ray is nearly filled with masses of 



yellowish green sub- 

 stance. This is a gland 

 which forms the diges- 

 tive fluids used in the 

 stomach. The wrinkled 

 mass in the region be- 

 neath the disk is the 

 stomach. The mouth is 

 just below the stomach 

 on the lower or oral side 

 of the body. At the 

 angles of the arms and 

 extending into each ray 

 are the reproductive 





Pi 



Figure 73. — Anatomy of the Starfish, glands, which vary in 



