141 



NOVELTIES. 



Type Slides. — At the meeting of the Quekett Club, on June 

 26th last, Mr. M. C. Cooke exhibited a very remarkable collection of 

 diatoms he had just received from J, D. Moller, of Wedel, in Hol- 

 stein; they were in number about 400, and were mounted on one slide, 

 called by the preparer a " Typen-platte," and were accompanied 

 by a key or catalogue. There was but little time to examine 

 and appreciate this extraordinary production then, and not much 

 information could be obtained about it in consequence, except 

 that similar slides might be obtained for about £3 each. 



Since then, Mr. Curties has jDlaced one of these " Type-slides " 

 in our hands for examination, and the impression produced is that 

 our German fellow microscopists are very far advanced in manipu- 

 lation. The slide is a most exquisite specimen of microscopic skill, 

 and better still, it forms a most useful typical collection of diatom- 

 acese. 



The slide we have examined contains 403 specimens and 387 

 distinct species ; these are mounted in balsam in a circular, glass 

 cell, covered by a disc, the first measuring .010, and the last .006 of 

 an English inch in thickness. It would appear from the uniformity 

 of focus that the diatoms are placed on the inner side of the 

 covering glass. A -j^^th objective of large angular aperture can 

 easily be used upon them. Fine specimens of EujJodiscus Argus 

 are placed as marks to indicate the commencement of lines. The 

 slide is accompanied by a written catalogue, neatly bound, in 

 which all the specimens are entered, and numbered in their proper 

 order. They are arranged as follows : — 



Epithemiese, 



M eridioneje, 



Diatomese, 



Tabellarie^, 



Surirelleffi, 



Nitzschiffi, 



Amphipleurese, 



Cocconeide^, 



AchnantheEe, 



CymbellesB, 



Gomph onomese, 



NaviculaceEe. 



Isthmeae, 



Biddulphiaceae, 



Eupodiscese, 



Milosirese, 



Chaelocerese. 



By slowly passing the slide across the field each specimen is 



