The Microscope. t9 



resrard to the form of the network of the frame. In the case of 

 Actinoptychus too much stress has been placed on mere size and 

 number of markings, for the so-called species run into each other 

 by intermediate forms in the Florida waters. I find a well 

 marked form, however, that I should call a new species since the 

 rays are connected by two granular ridges, near the centre of the 

 radius of the valve. As the valve is six rayed, the ridges form 

 two pentagonal figures. I would call it A. pentagonalis. The 

 general markings seem to resemble A. nitidus (Wolle's Diatom- 

 acese of N. A). I have as yet found but one specimen, but the 

 pentagonal zones are so conspicuous as to leave no room for 

 error. 



One of the most beautiful of Diatoms is Surirella Febegeriii 

 and it is by no means rare on the Florida coast. Another gem 

 of the first water is Amphiprora vitrea, or rather I will call it a 

 variety of that Diatom, and name it A. vitrea regalis. It is 

 twice the length of the figure in Wolle's Diatomacese of N. A., 

 being about .01 inch in length. This Diatom would make a good 

 test object, as it is very constant in size and striation. The lines 

 are transverse, about 60 to 1-1000 inch. The surface of the valves 

 is wav}^ lengthwise, so that the lines seem interrupted. It takes 

 a fine glass to show it well. 



ELEMENTARY MICROSCOPICAL MOUNTING.— Y. 



dr. a. m. webster. 



broavn's rubber cement. 



This is an almost colorless solution of pure rubber in benzol. 

 It is exceedingly thin, and for that reason somewhat difficult to 

 use until the microscopist has had a little experience with it, 

 when it becomes tractible and commendable for certain pur- 

 poses. Unless the brush is filled properl}^ with just enough to 

 do the work well the tendency is to run over the slip, where it is 

 not wanted. If the brush is too heavily loaded the cement will 

 spread irregularly over the slide, and the result will not be 

 pleasing; but if a little is used and several successive applica- 

 tions be made, the fluid is an excellent one. It is not to be com- 

 mended for the building up of cells, but as a finishing applica- 

 tion to a balsam mount, or to one cemented down with shellac or 



