SEA- ANEMONE:* LABORATORY WORK. 



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 

 they be used to indicate bilateral symmetry ? Make a 

 drawing of the animal showing the column, oral disc, etc. 

 Cut off a few tentacles, and see if they be hollow or solid. 



INTERNAL STRUCTURE. 



Cut the animal with a sharp knife into two portions, 

 the incision being made parallel to the oral disc and pass- 



* 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 every- 

 thing 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 soda (Glauber's salts); and 

 then, when completely stupefied, kill and harden by transferring to 

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

 then washed for half an hour in running water and transferred to 

 the preservative fluid formalin or alcohol (see Appendix). 



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