384 



Officers were then read, and the following members were 

 nominated to fill vacancies on the Committee : — Messrs. Ingpen, 

 Reed, Spencer, Mainland, and Priest. 



Mr. J. D. Hardy was also nominated and duly elected Auditor 

 on behalf of the members. 



Mr. Grenfell said he had brought for exhibition an excep- 

 tionally large specimen of Bhizosolenia rohusta (?), the largest 

 British diatom he had seen. It came from Plymouth. Its 

 length when complete was -^q inch at least, its breadth yl^ inch. 

 These dimensions are about IJ times those given in Pritchard's 

 figure, PI. 8, from Norman's MS. The fine markings are 

 rows of dots which he was unable to count ; Robusta has 

 about 55,000 to the inch. The specimen was stained with 

 methylen blue, which some diatomists might object to, but 

 he did not think it interfered in any way with the markings. 

 He had been working at a very interesting gathering from 

 Plymouth which contained several species of diatoms with the 

 pseudopodia-like filaments he had found in fresh water forms. 

 One of these species could not be found on slides of burnt or 

 acidised material ; it was apparently destroyed by these violent 

 measures. He therefore simply washed the material and dried 

 it on the cover glass. If this is put into styrax the more 

 delicate forms such as the one in question, asterionella, and 

 others vanish entirely or are so transparent as to be practically 

 useless, and are very trying to the eye to find. All traces of 

 the pseudopodia-like filaments vanish if any were present. The 

 addition of alcohol and a little methylen blue allowed to dry 

 on the slide remedies these defects to a certain extent. The 

 stained delicate forms are very much easier to see, which is a 

 great relief to the eye, and in some cases the filaments may be 

 stained also, as in the case of a Ooscinodiscus on the same slide. 

 But the method is not specially adapted to these filaments. 

 Styrax utterly destroys all markings on another new form in 

 this gathei'ing allied to Thalassiosira, whether stained or not. 

 In every gathering of diatoms some slides should be prepared 

 in this, or some similar way, if delicate forms are at all likely 

 to be present. 



Mr. Karop did not see that they were left to the alternatives 

 of bleaching or burning. Why not treat the protoplasm with 

 some fixing medium before mounting ? He feared it would be 



