SEA-ANEMONE. 



The following directions are drawn up for the common 

 anemone, Metridium marginatum, of the Atlantic coast. With 

 a few allowances they will apply to any form. It requires 

 some patience to prepare sea-anemones for laboratory work. 

 If merely collected and placed in the preservative fluid, the 

 result will be a shapeless mass, in which the student will find 

 everything confused. The anemones should be placed in 

 shallow dishes of salt water, allowed to expand, and then 

 gradually be stupefied by the addition of crystals of sulphate 

 of magnesia or sulphate of soda (Glauber's salts), and then, 

 when completely stupefied, kill and harden by transferring to 

 a 1% solution of chromic acid for three hours. The specimens 

 are then washed for half an hour in running water and trans- 

 ferred to the preservative fluid formalin or alcohol. 



EXTERNAL. 



In the prepared specimen notice that the body is cylin- 

 drical and may be described as consisting of a column, 

 with a base by which the animal was attached, and an 

 oral disc bearing a large number of finger-like tentacles, 

 in the centre of which is the mouth. Which tentacles, 

 inner or outer, are the larger? If there be an increase in 

 number of tentacles during growth, which ones would 

 probably be the older? What is the shape of the mouth? 

 How many thickened places do you find in the mouth? 

 These thickened portions are called siphonoglyphes. Could 



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