132 



NOTES AND CORRESPOx\UENCE. 



Gutta-perclia Troughs.— In case it slioulcl be thought worth 

 uoticCj I beg to oft'er the following suggestion . 



In Mr. James Smith's paper ''On a Dissecting Microscope/' 

 in the last number of the ' Journal ' (Trans., page 13), it is 

 remarked that ditFererit-sized objects would requii-e the slips 

 of glass at the bottom of dissecting troughs to be of different 

 widths, and therefore necessitate the employment of several 

 troughs, or else a glass trough furnished with several false 

 bottoms of gutta-percha, fitted with various-sized slips of 

 glass. 1 would venture to suggest that one gutta-percha 

 trough might suffice, if the aperture and glass fitted into it 

 were made loedye-shaped instead of paralled- sided, thus pre- 

 senting various widths at different points. An opening, an 

 inch and a half long, diminishing from half an inch in width 

 at one end to nothing at the other, would accommodate 

 various-sized dissections, and admit, if required, of their 

 being operated upon the same time. — G. Guyon, Richmond, 

 Surrev. 



« 



Microscopical Notes.— I inclose sketch of a Triarthra, of which 

 1 found several in a duck-pond at Chipstead, in Surrey, last 



August 



As nothing like it is described in the ' Micrographic 

 Dictionarv/ nor in the last edition of Pritchard, it may be new. 



