82 SELECTED NOTES FROM 



Aregma obtusatum. It is accompanied on the leaf by the orange 

 spores of a species of Lecythea, Cooke says, in the work above 

 referred to : — " The association of one-celled, orange-coloured 

 spores with the brown two or more celled spores passed in review 

 is another feature worthy of a passing notice, and which opens a 

 field for discussion. It is generally admitted that these two forms 

 are the production of the self-same mycelium or vegetative system, 

 but it is not so generally admitted that they are but two forms or 

 phases of the fruit of the same plant. It is not at all uncommon 

 in the history of mycology to find two forms which were for a 

 long time considered to be distinct plants producing different 

 forms of fruit, and which bore different names, and were located 

 in different genera, at length proved to be only the self-same plant 

 in different conditions, and ending in one name being expunged 

 from the list. Such a fate probably awaits, at no distant date, the 

 orange spores which precede or accompany the species in the 

 present genera (p. 74). T. Whitefoot, Jun. 



Desmids.— One of the peculiarities of desmids is their exceeding 

 symmetry, each half of the cell (for though apparently double, it is 

 really single, as is shown if a puncture is made, the whole cell- 

 contents being emptied) being identical, the same number of 

 starch-grains, if they exist, being shared equally in the same rela- 

 tive places (the same with chlorophyll, etc.) ; this bilateral arrange- 

 ment is, if I may use the term, very animal-like. 



These organisms are best examined in their fresh state. On 

 the slide the cell-walls show most distinctly ; the interior contents, 

 however, are not so clear. This, perhaps, is unavoidable in 

 mounted specimens. J- Vereker. 



Starch-Grains. — To recognise starch-grains, the best way is to 

 place a drop of dilute aqueous solution of iodine in iodide of 

 potassium in the water on the slide ; the starch is coloured blue. 

 Of course, the polariscope may be used instead, but the first 

 process is very convenient, as it gives a blue colour, and the 

 polariscope can be used as a confirming test. J. Vereker. 



Palates of MoUusca for Polariscope. — These organs, sometimes 

 called "tongues," are very curious." They are armed with sharp 

 teeth, and differ as much in the molluscs as the antennae in the 



