26 G. T. HARRIS ON DESMIDS. 



species in the genus Closterium. Penium spirostriolatum is 

 really only interesting when the empty cell can be procured. 



It may appear somewhat paradoxical, while holding the view 

 that the interest of a mounted desmid is really very limited, that I 

 should ask the Club to accept for its Cabinet a small collection 

 of mounted desmids. The reason is, I hope, sufficiently obvious. 

 Many microscopists without becoming serious students of a group 

 are sufficiently interested in it to desire an acquaintance with its 

 principal forms. Further, the variety of species obtainable in the 

 collecting districts around London has no comparison with those 

 to be got from alpine and sub-alpine situations, so that species of 

 very considerable interest may never come in the way of the 

 metropolitan collector unless he sees them as mounted slides. My 

 only hope is that some measure of useful life may be granted to 

 the small collection of slides I ask the Club to accept. 



Journ. Qwkett Microscopical Club, Ser. 2, Vol, JIII,, iVo. 78, April 1916. 



