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PEOCEEDINGS OF THE MALACOIOGICAL SOCIETY. 



a form which is readily obtainable for comparison. It should, how- 

 ever, be added that in young specimens of Littorina there are traces 

 of the 'fans' which characterise the other two forms mentioned. 

 In other cases they may be present where they have not been figured. 



The largest blanks in our knowledge are probably those occasioned 

 by imperfect methods of preparation, mounting, and microscopical 

 examination. Styrax is the best mounting medium I have yet found ; 

 but excellent preparations can be made by simply drying the specimen 

 on the slide and covering in air, a clean coverglass being laid on the 

 object and secured in place with a piece of stamp-paper in which 

 a hole has been cut. 



