STARFISH 79 



8. A statocyst occurs on the dorsal surface of the basal joint 

 of each antennule. Remove the rostrum and locate opening of 

 statocyst by means of a blunt probe. 



EXCRETORY SYSTEM 



i. The kidneys or green glands lie in the ventral part of 

 the head anterior to the mouth. Each kidney connects with the 

 exterior on the posterior surface of a tubercle located upon the 

 basal segment of the antenna. 



REFERENCES 



Andrews, E. A., 1906. The Keeping and Rearing of Crawfish for 

 Class Use. Nature-Study Review: Vol. 2, pp. 296-301. 



Herrick, F. H., 1911. Natural History of the American Lobster. 

 Bull. U. S. Bureau Fisheries 29. 



STARFISH 

 (ASTERIAS) 



Classification: Phylum Echinoderma, Class Asteroidea. 

 The starfish will be studied as a representative animal in 

 which the organs are duplicated, more or less perfectly, about a 

 central axis, and therefore it is said to be radially symmetrical. 

 During this study look for structures which prevent the starfish 

 from being a perfectly radial animal. 



As this kind of animal differs so much in structure from the 

 other animals you have studied it will be very important to keep 

 in mind the functions of the different organs, as functional rela- 

 tions to other animals are more readily understood than its struc- 

 tural relations. 



The entire study, including the dissection, must be made from 

 a single specimen. 



