CHAPTER VII 
ECHINODERMATA 
ASTEROIDEA 
A STARFISH 
Several species of starfishes are common along our coasts, 
the most familiar being Asterias vulgaris, the common New 
England form, which is found along the entire Atlantic coast, 
and Asterias forbsii, which is found south of Cape Cod. 
They are remarkably sluggish creatures which live on the sea 
bottom, moving slowly, often in large numbers, from place to 
place and feeding on the various mollusks which come in 
their way. 
Two specimens will be needed for this dissection, a dried one 
for the study of the hard parts, and one that is fresh or has 
been preserved in formalin or alcohol for the study of the inter- 
nal and other soft parts. To prepare a dried starfish the live 
animal should be placed in fresh water for half an hour. It 
should then be placed in alcohol for an hour, and then dried 
thoroughly. If only preserved material be at hand the animals 
may be simply dried. The fresh water and alcohol expand the 
body-wall of the animals and prevent it from collapsing after 
death. 
Study the external characters of a fresh or a preserved speci- 
men. Observe the color and the flattened radiate body-form. 
The body is composed of a central disc from which radiate five 
arms or rays. All of these rays are normally of equal length. 
Specimens are often found, however, in which the length of 
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