244 ECHINODERMATA (tHE STARFISH) 



(b) Shape? 



(c) Any teeth? 



(2) The Stomach is a large sac-Uke organ filUng most of 



the disk. Inflate it or fill it with water to distend it. 

 Does any part of the stomach reach out into the rays? 



(3) Hepatic Ceca, digestive glands or livers. In each arm 



find elongated, branched brown or green bodies or 

 organs. 



(a) Size? 



(b) Shape? 



(c) Position? 



(d) Number in each arm? 



(e) Where do they unite? 



(f) Into what do they empty? 



(g) Use? 



(4) The Mesentery. Trace it as it holds the ceca together 



and suspends them from the aboral wall. 



(5) The Extensor Muscles. Find them along the center of 



a flap of a ray which you have turned back. 



(a) Shape? 



(b) Color? 



(c) Size? 



(d) Use? 



(6) The Intestines are slender and short, leading from the 



stomach to the vent. 



(a) Why are they so short and weak? 



(b) How does the starfish feed? 



(c) What is its food? 



2. The Reproductive System. The reproductive organs or 

 gonads are found along with the hepatic ceca in the floor of each 

 ray. They are usually smaller and more grape-like. 



(1) Shape? 



(2) Size? 



(3) Color? 



(4) Number? 



(5) Where do they unite? 



(6) Use? 



3. Sketch the plan of the digestive and of the reproductive 

 systems. 



