517 



The next is by J. Badcock, Journ. R.M.S. vol. 4, ser. 2 (1884), 

 p. 352, figs. 49 and 50, on Surirella hifi^ons. The next is by 

 J. G. Grenfell, Journ. R.M.S. (1893), p. 806, and (1894) p. 415. 

 These are very important. And finally by Lewis Wright in his 

 handbook to the microscope, p. 233 footnote (1895). 



As Mr. Grenf ell's views did not agree with those of Mr. 

 Bennett, the botanist-abstractor of the R.M.S., his papers were 

 never published ; a brief note is given of them in the Proceeding's. 

 I saw Mr. Grenfell's exhibits both at the B.M.S. meeting and 

 subsequently in my own study. These references are of im- 

 portance because Mr. T. Comber's remarks are given, and he 

 was the greatest authority on the Diatom aceae either here or 

 anywhere else. Mr. Grenfell's pseudopodia were like Mr. Wood's, 

 whereas Mr. Siddall's are more like Mr. Badcock's. 



RHABDONEMA MINUTUM. 



By N. a. Brown, A.L.S. 



(^Exhibited May Uth, 1912.) 



This slide of a marine diatom collected at Douglas, Isle of Man, 

 and originally preserved in sea-water and formalin, demonstrates 

 that it is possible to mount this and probably other diatoms in 

 styrax in such a manner that the form of the chromatophores 

 is preserved. To get rid of the salt and formalin the material 

 was well washed in distilled water, then transferred to a cover- 

 glass, and the water allowed to evaporate slowly from the outside 

 of the diatom, but not from the interior. At the critical moment, 

 when it was judged that this had been accomplished, a drop of 

 styrax was placed on the diatom, and the mount made. 



The water has dried from some of the frustules, and into these 

 styrax has penetrated. The result is rather remarkable, for in 

 those frustules containing water not only are the chromatophores 

 fairly well preserved, but the structural markings of the diatom, 



