200 BIBLIOGBAPHY. 



deeply indebted to Mr. Ackland for coming among them, but also for 

 the valuable information be bad afforded tbem. 



Mr. Sewell seconded tbe resolution, wbicb was carried unanimously, 



A very large number of polarizing objects of a varied character 

 were then exhibited, with and without tbe selenite stages, by Messrs. 

 Sewell, Turner, Ackland, C Smith, Glaisyer, and Wonfor ; and general 

 satisfaction was expressed at the results and the increased beauty with 

 the neutral background. 



Mr. Hennah also exhibited Dr. Pigott's Aplanatic Searcher, 

 kindly lent by Mr. dirties, and Dr. Maddox's jiboto-casts of diatoms, 

 ranging from 900 to 3000 diameters, kindly lent by Gen. Worcester. 



Mr. Wonfor exhibited a Searcher suggested by JVIr. Mclntire, con- 

 sisting of an objective arranged in the di'aw-tube, with its observing 

 end turned to the eye-pieee, and a simple mode of mounting an 

 objective under the stage to be used as a condenser, at any angle, as 

 suggested by Dr. Matthews, and the new slide with movable brass 

 cover for dry objects. 



BIBLIOGEAPHY. 



Berichte ueber die Verbandlungen der naturforschenden Gesell- 

 schaft zu Freibui'g von Professor Maier. Freiburg. Troemer. 



TJntersuchimgen ueber die Entwicklung der Emjmsa muscoe und 

 Emjmsa radicans und die durch sie veriu'sachten Epidemien der 

 Stnbenfliegen und Raupen. Von Dr. Oscar Brefeld. Halle. 

 Schmidt. 



Beitrage zue Anatomic und Histologic des mittleren Ohres. Von 

 Dr. Gustav Brunner. Leij)zig. Engelmann. 



Die Sculptur und die feineren Struckturverhaltnisse der Diatoma- 

 ceen. Von Dr. Gustav Fritsch und Otto Miiller. 12 Taf. Mikro- 

 photogr. Berlin. G. F. 0. Miiller. 



Sitzungsberichte der naturwissenschaftlichen Gesellschaft Isis in 

 Dresden. Hrsg. Von Carl Bley. Dresden. Schopff. 



Sitzungsberichte der Konigl. bayer. Akademie der Wissen- 

 schaften zu Miinchen, 1870. Miinchen. Franz. 



Beitrage zur Theorie der natiirlichen Zuchtwahl von Alfred 

 Eussell Wallace. Translated by Adf. Bernh Meyer. Erlangen. 

 Besold. 



