PROCEEDINGS OF THE COTTESWOLD CLUB 215 



a single wheel of Chirodota: it has 6 rays, and is 

 ■00425 in. in diameter (See Plate A, fig. 16). 



Various methods are recommended in the Micrographic 

 Dictionary and other works for the preparation of the 

 Chalk Microzoa for examination with the microscope ; but 

 in my hands no process has been so successful as the 

 following: — For Foraminifera, Ostracoda, Polyzoa, and 

 such sponge spicules as are free in the chalk, my plan is to 

 procure the very soft chalk from the deep hollow cavities on 

 the exterior of freshly extracted flints : while damp this has 

 somewhat the consistency of putty, or clay, and contains the 

 most perfect and the largest organisms, and a greater number 

 of spicules than chalk taken from a distance from flints. 

 This soft chalk, upon being placed in water, immediately 

 breaks up and falls to the bottom of the vessel in a kind 

 of mud, without the need of any brushing or other 

 pulverising process. The chalk and water should be 

 shaken and allowed to settle, and the w^ater poured away a 

 good many times, regard being had to whether the smaller 

 forms are required or not, and as a rule this wall be found 

 sufficient ; if, however, the organisms are not found to be 

 perfectly clean, a good boil in strong soda, and decantation, 

 will invariably be found sufficient. Care should be taken 

 in the soda-process to keep the test tube continually 

 in rapid motion, otherwise it is apt to spurt and so eject 

 the organisms. 



The soft chalky material from the interior of hollow 

 spongeous flints frequently contains good specimens of 

 sponge spicules. This can be treated with acid, as the 

 spicules are silicious. The preparation and mounting of 

 sections of Flint and Chalcedony is, of course, best left to 

 the lapidary ; but sections of test, Echinid spines, and stems 

 of Crinoids are easily made by grinding down upon a hone 

 in the usual way " they should be mounted in Canada 



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