1 Transactions of the Society. 



The sketch of Mr. Macdonald's Fijian plant from which my figure 

 has been taken is on too small a scale to show whether the median 

 lobe has a smooth or a rough shaft. 



As a matter of strict classification, perhaps, a regular series 

 might be formed from the whole genus Micrasterias, even such 

 apparently dissimilar plants as 31. denticulata Brebisson, and 

 M. dichotoma Wolle, which might be placed at opposite poles, ex- 

 hibiting the generally trilobate form characteristic of the whole 

 series. To some extent the same might be done in other genera, say 

 Cosmarium, Staurastrum, or Closterium ; but in these the gradations 

 would not be nearly so easy to find at present. Micrasterias, a small 

 genus of few species which run almost into one another, offers a good 

 opportunity for some such simplification as I have endeavoured to 

 effect in one case. 



There is, as has been hinted above, a slightly wider gap between 

 my No. 6 and No. 7, than between any two others, and probably 

 this is an inducement to separate my series into two. Still, the gap 

 is so slight that I think it may be disregarded, and it only needs the 

 finding of one specimen of either of these two plants varying the 

 least bit either way, to fill it up as much as in other cases. 



The suggestion which I have made may be, perhaps, by some con- 

 sidered trivial, and taken per se is of course only interesting to students 

 of the Desmidieee. Yet I venture to express the thought that it may 

 have a wider bearing, and that future generations of workers in 

 science may not be over-thankful to those who, with the very best 

 intentions, are nowadays multiplying " species " with such exuberant 

 fertility. The remark applies to all branches of zoological and 

 botanical inquiry as far as my experience extends. At the present 

 rate, the papermakers and bookbinders profit greatly, and the shelves 

 groan more and more under the weight of books ; but there is pro- 

 spect of much trouble and weariness for future students. 



