278 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXII. 



In order to mount the radula as an object for the microscope it 

 may be obtained from a large species by dissection and then cleaned 

 by boiling in a not too strong solution of caustic potash., A word of 

 warning is necessary, however, that the largest species do not always 

 possess the largest radulae. 



With small species the proboscis or buccal mass, or even the 

 whole animal, may be boiled until nothing is left but the clean 

 radula. The radula can then be washed and mounted, the best 

 medium for the purpose being glycerine jelly, which should be run 

 in under the cover-glass after the latter has been clipped over the 

 specimen. Air bubbles can be removed by a momentary boiling 

 and the specimen should then be left for some week& after which 

 the superfluous jelly may be cleaned away and the slide finished by 

 ringing, first with microscope cement and then with gold size. 



The author , would be glad to furnish further notes on preparing 

 and mounting specimens to anyone who should be interested in the 

 subject or to prepare examples for the Society from any fresh 

 material that may come to hand. The material cannot be too 

 common or apparently insignificant, for instance, Planaxis sulcatus, 

 which is very common and has a most unattractive shell, furnishes 

 us with one of the most beautiful radulse. 



It should be noted that .many of the radulae are particularly 

 beautiful objects when viewed with, the polariscope. 



