01' THE SPONG1AD.E. 225 



On the Preservation and Examination of the Spongiadce. 



The greater portion of specimens in natural history may 

 be readily examined and their species determined in the 

 field ; but this is rarely the case with the Spongiadse. It 

 becomes necessary therefore to preserve them in such a 

 manner as to effectually retain their natural characters for 

 examination at some future period. Small specimens may 

 be preserved in spirit of wine, but this destroys their colour. 

 If they are not likely to be permanently lodged in the 

 cabinet immediately, it is better that they should be laid on 

 blotting paper, or a soft cloth, to absorb as much as possible 

 of the water from within them and then dry them rapidly 

 before a fire, or in a slack oven, without any previous 

 washing in freshwater. By this mode they retain a sufficient 

 amount of moisture and flexibility to allow of their being 

 handled and operated on for examination with impunity ; 

 but the amount of salt thus left within them will in time 

 cause considerable mischief to the specimen. After such 

 specimens have been once thoroughly dried and their ex- 

 amination has been completed, they may be plunged into 

 cold water for a few minutes, and the water then ejected by 

 a rapid centrifugal motion of the arm, and this operation 

 repeated two or three times ; the specimen should be again 

 rapidly dried, and it will then keep well in the cabinet and 

 preserve all its characteristic features. It is a bad habit to 

 soak marine specimens for a considerable time in fresh 

 Avater to extract the salt, as by this mode of proceeding the 

 minute and delicate characters of the object are to a great 

 extent destroyed. 



The most advisable mode of proceeding in the examina- 

 tion of an unknown species, is first to note the general 

 peculiarities of form and surface as presented to the unas- 

 sisted eye. 



After the noting of the external character, the next step 

 should be to cut a slice out of the sponge, to about half an 

 inch or more in depth at right angles to the surface, taking 



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