312 THE FOEAMINIFEEA 



mounting the little tests are the finest red sables, 

 which should have a fine and fairly flexible point. 



An ingenious mount for showing opaque objects, 

 such as Foraminifera, in various positions by a turn- 

 ing arrangement has lately been described by J. J. 

 Harvey in the following words : ' One of the many 

 objections to the present system of mounting opaque 

 objects is that it is necessary to permanently hide 

 one side of the specimen, and in the case of aberrant 

 or rare forms this may greatly lessen the value and 

 interest of the slide. The method here advocated 

 allows of the revolution of the object under the 

 microscope, and permits of its examination with as 

 much ease as a hand specimen. It is at the same 

 time as permanent and as compact as the older 

 system. Another important advantage is the 

 differential lighting which this rotation brings into 

 play, and which the inventor has found of special 

 service in the study of the Foraminifera for which 

 this method was originally designed. The slides 

 used are the wooden slips recommended for this 

 class of objects by Carpenter and others. The 

 specimen is attached by means of a suitable medium 

 to the end of a needle (fig. 42 b) which has been 

 thrust through the centre of a plug of indiarubber 

 cord C. This is laid, with the specimen projecting 

 into the central cell D, in a shallow longitudinal 

 groove A cut just deep enough to enable the speci- 

 men to revolve without touching the cover-glass, a 

 hole also having been cut for the reception of the 

 rubber plug. The projection of this plug above the 



