Digest of Current Literature. i6i 



ber of the Ainerican Naturalist for 1878, the advantages of slides 

 measuring 25x45 mm. over those 3X1 inch, were stated to be as fol- 

 lows : (i) They can be rotated on the stage ; (2) they are less liable 

 to break if dropped ; (3) they take up less room. It was also stated 

 that this size was adopted by the New York State Museum of Natural 

 History, and by lithologists and palaeontologists generally, both in 

 Europe and America. 



These arguments seemed to me quite as valid as applied to microscop- 

 ical objects in general; I therefore adopted this size (25 x 45 mm.) formy 

 own preparations, and they have proved very satisfactory indeed. 



S. H. Gage. 



DIGEST OF CURRENT LITERATURE. 



It is intended to make this a valuable record of the work going on throughout the world. 

 As may be readily understood, it is impossible to make the record complete in our first one or 

 two numbers For the accuracy of these abstracts the Editor holds himself personally responsi- 

 ble. Reprints will be noticed only by title, as a rule. 



THE JOURNAL OF THE ROYAL MICROSCOPICAL SOCIETY 



November, 1878. 

 On the Fossils called "Granicones; " being a contribution 

 TO THE Histology of the Exo-skeleton in Reptilia. — Professor 

 Owen.— The name " Granicone " was applied by the author to designate 

 certain bodies found in the "feather-bed stratum" of Dorsetshire. 

 From microscopical examination of thin sections it is concluded that 

 " the granicones are dermal scutes, that they are Lacertian, and, as far 

 as contiguity and association indicate, have formed part of the extert 

 nal armor of the large, extinct Purbeck Lacertian, Nuthetes destructor." 



On some New Genera and species of Diatomace^. — P. Petit. — 

 Translated by F. Kitton. 



Further remarks on a "Simple Device" for the Illumina- 

 tion of Balsam-Mounted Objects, for Examination with Im- 

 mersion Objectives whose Balsam-Angle is 90° or upwards. — 

 J. J. Woodward, Surgeon, U. S. A. — Dr. Woodward mounts his prism 

 by cementing the truncated right-angle to a piece of brass upon the 

 end of a straight rod. The rod is slipped into the holder of the dark- 

 well. 



THE JOURNAL OF THE QUEKETT CLUB. 



October, 1878. 

 On an Apparatus for Facilitating the Use of " Powell's 

 Small Bulls-eye" Illuminator in the Resolution of Test 

 Objects.— Geo. Williams.— The diatoms are mounted upon a circular 

 disk of glass, supported on a holder. The flat side of the condenser 

 is placed next to the disk, thus condensing the light very obliquely 

 upon the frustule. The disk can be revolved to place any diatom in 

 the proper direction. 



