218 ECHINODERMATA 



macerate a portion of an arm to see the skeleton to which 

 these muscles are attached. 



Study prepared sections of the arm of a small starfish and 

 determine the relation of organs. 



1. The hepatic caeca. How are they supported? What 

 is their structure? 



2. The radial canal, connecting tubes, tube feet, and am- 

 pullae. 



3. The thickened, deeply stained, radial nerve between the 

 tube feet and below the radial water tube. 



4. The perihemal canal, divided by a thin partition, that 

 lies between the radial water tube and the radial nerve. 



Make a drawing of a section of an arm that will show 

 these points. 



Understand how a starfish can open an oyster or a mussel 

 and how it digests it when open. How can it digest a bar- 

 nacle or small snail? How does it respire? 



Chadwick, H. C: Memoir No. 25. Asterias. Liverpool Marine Biol. 



Committee, 1923. 

 Cole: Experiments on Coordination and Righting in the Starfish. Biol. 



Bull., 24, 1913. 

 : Direction of Locomotion in Starfish, Asterias forbesi. Jour. 



Exp. Zool., 14, 1913. 

 Field: Larva of the Asterias vulgaris. Quart. Jour. Mic. Sci., 34, 1892. 

 Gemmill, J. F.: The Development and Certain Points in the Adult 



Structure of the Starfish, Asterias rubens. Phil. Trans, of the Roy. 



Soc, London, Series B, vol. 205, 1914. 

 Hopkins, A. E.: On the Physiology of the Central Nervous System in 



the Starfish, Asterias tenuispina. Jour. Exp. Zool., vol. 46, No. 2, 1926. 

 Jennings: Behavior of the Starfish Asterias forreri. Univ. Calif. Pub. 



Zool., 4, 1907. 

 MacBride: Development of Asterias gibbosa. Quart. Jour. Mic. Sci., 



38, 1896. 

 Mead: The Natural History of the Starfish. Bull. U. S. Fish Com., 



1899. 

 Tennent and Hogue: Studies on the Development of the Starfish Egg. 



Jour. Exp. Zool., 3, 1906. 



