1894.] MICROSCOPICAL JOURNAL. 27 



the clamping screw which its stem perforates ; while the 

 outer is intended to allow the body to be swung to one 

 side through an angle of 90,° when a simple lens mounted 

 on another stand is to be brought oyer the dissection — 

 a necessity only likely to be foreseen by a anatomist. 

 The tube of the microscope itself is so evidently adapted 

 from fig. 3 as to need no observation, and the only 

 novelty is that it is double within, so as to permit of the 

 use of a second objective above the first, as an erector, 

 an original feature for which Strauss- Durckheim can also 

 claim priority. 



( To be concluded in February.') 



The Bacillariaceae or Diatomaceae. 



By ARTHUR M. EDWARDS, M. D. 



NKWARK. N. J. 



As it is intended, if the subscribers are enough in num- 

 ber, to publish a treatise or book on the Diatomacea*, and 

 as it is proposed to use for the title a new reading of the 

 name, namely the Bacillariaceae, it will be well herein as 

 well as in the future to explain what is meant by the term 

 used to designate this wonderful and beautiful group of 

 organisms. 



Availing himself of the writings of the late Rev. Eu- 

 gene O'Meara, in 1872, in the Quarterly Journal of Mi- 

 croscopical Science in his " Recent Researches in the Dia- 

 tom acew "when reviewing Dr. E. Pfitzer's" Untersuchun- 

 gen uber Bau und Entwicklnngen der Bacillariaceen 

 (Diatomaceen) " he pens the following. 



The name Diatomacejp has been used by nearly all the 

 more recent authors to designate the grou}). Rabenhorst, 

 in his more recent work " Flora Europaea algarum aquae 

 dulcis et stibmarinsp," 1864-1868, has adopted the name 

 Diatomophycesp for the group. But in his former trea- 

 tise Die Susswasser Diatornaceen 1853 he used that of 



