PROCEEDINGS OF THE SOCIETY. 117 



sent to them by Messrs. Bauscb. and Lomb. It consisted of an upright 

 pillar mounted on a firm base, and carrying an eye-piece which consisted 

 of two right-angled prisms cemented together and silvered on their 

 facing surfaces with the exception of a small hole, and having a third 

 prism cemented to these. The pillar also supported a rigid arm, which 

 carried a mirror at each extremity fixed at an angle of 45° to the hori- 

 zontal. The object to be drawn was placed under one of the mirrors, 

 and the paper on which the drawing was to be made was similarly placed 

 below the other, the image being seen through the eye-piece projected 

 upon the paper, on which it could easily be traced with a pencil. 



The thanks of the Meeting were voted to Messrs. Bausch and Lomb 

 for sending this apparatus for exhibition, and to Mr. Rousselet for 

 explaining it. 



Mr. E. M. Nelson's note on a Two-speed Fine Adjustment was read 

 by Mr. Vezey, and illustrated by a diagram drawn upon the board. 



The thanks of the Society were voted to Mr. Nelson for his com- 

 munication. 



The Rev. R. Freeman read a paper, by Mr. F. R. Dixon-Nuttall and 

 himself, ' On the genus Diaschiza,' 1 which was illustrated by a number 

 of drawings shown upon the screen by means of the Epidiascope. 



The President, in moving a vote of thanks to Mr. Freeman, said it 

 was obviously impossible to judge fully of the merits of an exhaustive 

 paper of this kind from simply hearing it read, but they would look 

 forward to reading it for themselves in the Journal, with the beautiful 

 illustrations they had seen exhibited before them in the plates accomr 

 panying the text of the paper. 



Mr. C.F. Rousselet said : The paper on the genus Diaschiza to which 

 we have been listening will be welcomed by all students of the Rotifera. 

 It is one of those which has required a very great deal of work — work 

 of some years indeed, and much more than appears on the surface of it. 

 For I know by experience how difficult it is, and how long a time it 

 takes to check all the reported facts and find out the mistakes or inaccu- 

 racies of previous students of such an obscure and difficult group of 

 Rotifers as the genus Diaschiza. 



The mistakes were due mostly to the imperfection of the tools with 

 which these predecessors had to work, but they were none the less 

 mistakes, likely to lead astray, and involving considerable work to find 

 out and correct. I think the authors are to be congratulated on the 

 success with which they have revised this genus, and also on their good 

 fortune in having found all the well authenticated species in their 

 neighbourhood. The fine figures which we have seen on the screen, 

 drawn by Mr. Dixon-Nuttall, are so good and full of detail, that the 

 identification of the species will no longer offer the difficulties which it 

 formerly did. 



It will have been noticed that several well-known names will have 

 to disappear as synonymous, such, for instance, as Diaschiza semiaperta, 

 which is obviously identical with Furcularia gibba of Ehrenberg, and 

 will now be known as D. gibba. 



