268 PROCEEDINGS OF THE 



this stage every condition up to seven or eight fully grown diatoms 

 in the same cyst may be observed. The young ones move about 

 until nearly fully grown, when they arrange themselves into a 

 barrel-shaped mass and develop endochrome. Eventually the 

 sheath disappears and the diatoms become free. Indications 

 of growth, such as division of the cells, have been observed 

 by Mr. Brown in mounted specimens, and a photograph of an 

 Arachnoidiscus was shown in which such division could be seen, 

 and the method by which new sections were added to the disc 

 was described in detail. 



A hearty vote of thanks was accorded to Mr. Brown for his 

 paper. The Secretary announced that Mrs. O'Donohoe had 

 presented to the Club a collection of her husband's photographs, 

 and he was directed to send a letter of thanks to her for her 

 kind gift. 



At the 561st Ordinary Meeting of the Club, held on May 10th, 

 the President, Dr. A. B. Rendle, M.A., F.R.S., in the chair, the 

 minutes of the meeting held on April 12th were read and con- 

 firmed. 



Mrs. D. C. Davies, Mrs. M. D. Edmunds, Messrs. Ernest Harold 

 Newman Skrimshire, Sydney V. King, D. C. Davies, Frederick 

 M. Jones and Arthur Edmunds, B.Sc, C.B., M.S., F.R.C.S., 

 were balloted for and duly elected members of the Club. Two 

 nominations were read for the first time. 



The Hon. Secretary announced that ninety-seven pathological 

 slides had been presented to the Club by Mr. Maurice, and that 

 a copy of Contributions to the Biology of the Danish Culicidae, by 

 C. Wesenberg-Lund, had been received from the author. The 

 thanks of the Club were accorded to the donors. 



The Hon. Secretary read a note from Mr. Nelson on " Aula- 

 codiscus Janischii Gr. and St." Mi. Nelson has recently dis- 

 covered the secondary structure of this diatom capping the 

 primaries. The valve must be examined from the inside, as the 

 structure is invisible from the outside. Mr. Merlin had confirmed 

 the image, which he stated to be " very difficult and evasive." 

 The structure was seen with a 1/12 in. apo., and illumination was 

 obtained from the edge of the flame of a half-inch wick by a 

 Holos condenser oiled on and working at full aperture. A 

 peacock-green screen was used. 



