April, 1910.] THE VICTORIAN NATURALIST. 195 



the use of a 2-inch or i-inch objective. A convenient sorting 

 tray may be made of vulcanite, with a projecting ^^^j-inch 

 rim, the slide being made slightly larger than the ordinary 3-inch 

 X i-inch slide. 



Mounting Foraminifera. — For dry mounting a cheap and 

 convenient slide may be made of a slip of 3 x i-inch wood, 

 bored with a central hole of ^-inch or %-inch diameter, or of 

 thick cardboard of the same dimensions, perforated by a hole 

 made with a gun punch. The wood or cardboard slip can then 

 be glued to a piece of thin card, on which a patch of indian ink, 

 slightly larger than the hole in the slide, has been painted. 

 Where cabinet space is limited and specimens numerous, many 

 shells may be mounted on one slide in which the cell is large, 

 rectangular, and divided into spaces which are numbered. This 

 can be covered with removable glass, and a reference index kept 

 for each slide. The specimens may be gummed on separately, 

 or, as in the composite slide, the whole surface may be prepared, 

 and the specimen secured by the application of the moistened 

 tip of a fine brush. To attach the specimens gum arable may be 

 used, but it should be rendered tough by the addition of a itw 

 grains of sugar or a few drops of glycerine to each ounce of 

 liquid gum. A drop of oil of cloves introduced will prevent 

 mould. Gum tragacanth gives good results, as it dries with a dull 

 surface. It requires a little practice in its use, however, as it has 

 the consistency of a stiff paste. 



Transparent mounts of foraminiferal shells involve the cleaning 

 of the tests. This is done by boiling in a weak solution of 

 caustic potash, to remove the organic matter. After careful 

 washing the material may be passed through absolute alcohol, 

 turpentine, and finally into Canada balsam dissolved in xylol, in 

 which it is mounted. If left long enough in the turpentine bath 

 all air bubbles will be removed. In mounting, the heat employed 

 should not be so great as to cause vapour bubbles to form in the 

 liny chambers of the shells ; and to obviate this a steam bath 

 should be used. 



Explanation of Plate. 



Fig. I. — Recent Foraminifera from St. Kilda beach. This sand contains 

 the following Foraminifera: — Miliolhta seminulum, L. , sp. ; M. subrotunda, 

 Mont., sp. ; Discorbina dimidiata, P. and J. ; and Polystomella macella, F. 

 and M., sp. Also separate valves of the ostracodes Loxoconcha, sp., and 

 Cythere canaliculata, Reuss ; together with numerous spines of Echinocardiuni 

 austrah. Gray. x dr. 26. 



Fig. 2. — Fossil Foraminifera, &c., from washings of Tertiar)- clay (Bal- 

 combian age), at Balcombe's Bay, near Mornington. Containing the follow- 

 ing Foraminifera : — Bolivina ptiiictata, d'Orb. ; Lagena dis/oma, P. and J. ; 

 L. sulcata, W. and T. ; Cristellaria crepidula, F. and M.. sp ; and Globigenna 

 bttUoides, d'Orb. Also a radiolarian, Haliomma, sp. ; numerous shells of the 

 pteropod, Limacina iertiara, Tate, sp. ; and calcareous spicules of an ascidian. 

 ■; cir. 26. 



The photomicrographs are taken from slides in the cabinet of the National 

 Museum by permission. 



