QUEKETT MICROSCOPICAL CLUB. 109 



The best focal plane for the " pseudopodia " does not coincide 

 with that for the diatom itself, and this, together with the 

 prolonged exposure necessary to bring out the faintly illuminated 

 filaments, causes the valve to be much over-exposed, making 

 the diatom appear as a mare blurred, globular white patch in 

 the print. 



The President gave a resume of a communication of some 

 length by Mr. W. M. Bale, F.H.M.S., of Victoria, Australia, 

 entitled " Notes on Some of the Discoid Diatoms." This paper 

 was a survey of some of the principal characters which have 

 been utilised in the discrimination of species in three or four 

 of the best-known genera of discoid diatoms. Some of the 

 conclusions arrived at as to the inadequacy of many of these 

 distinctions have been reached by previous observers, more 

 especially in the genus Coscinodiscus ; but it was thought that 

 in such cases the special instances now brought forward might 

 be serviceable in reinforcing those conclusions. In other cases, 

 particularly in the genus Actinoptychus, the author's observa- 

 tions tended to prove that characters accepted as specific even 

 by recent authors were demonstrably unreliable. The genera 

 dealt with included Coscinodiscus, Actinocyclus, Asteromphalus 

 and Actinoptychus. 



The thanks of the meeting were unanimously voted to the 

 President for communicating this important paper. 



A paper on " British Freshwater Bhabdocoelida (Planarians), 

 a Group of Turbellaria," by H. Whitehead, B.Sc, in the absence 

 of the author was read by Mr. J. Wilson. 



After some discussion, in which Messrs. Scourfield and Ham- 

 mond took part, the President said that the Bhabdocoelids were 

 very low down in the scale, some of them ranking among the 

 lowest of multicellular organisms. Most of his own work in 

 Australasia had been done on land forms, but there were, pos- 

 sibly, water forms as well. There were in Australia an enormous 

 number of land Planarians which lived under stones, rocks, logs, 

 etc., and only came out at night. Some were very large, reach- 

 ing a length of one foot. They are locally incorrectly termed 

 " land-leeches." Many are brightly coloured in stripes, spots, 

 and patches of brilliant blue, red, yellow, orange, and sometimes 

 iridescent. These colourations were very useful in assisting 

 naturalists to identify species. He had described some forty new 



