110 
THE JOURNAL OF BOTANY 
prepared by a joint committee, the present list being taken as a 
general basis. 
3. Treatment of generic homonyms as non-valid, with the excep¬ 
tion of such as may be placed on the list of “ nomina conservata.” 
4. Treatment of all specific homonyms as non-valid. 
5. Abandonment of priority of position. 
6. Abandonment of an obligatory Latin diagnosis of new groups ; 
with a recommendation, however, that a Latin diagnosis should be 
supplied, especially in cases where descriptions are published in lan¬ 
guages which do not employ Roman characters. 
7. Treatment of generic names as non-valid unless they are 
accompanied by a generic description or a reference to a former 
description (generic or sectional). 
8. Treatment of generic names as non-valid unless they are asso- 
ciable with a simultaneously or previously published binomial specific 
name. Provision, however, to be made for the typification of im¬ 
portant genera which would otherwise be invalidated under this rule. 
9. Acceptance of duplicate binomials. 
FRESHWATER PLANKTON AL(LE FROM CEYLON. 
By W. B. Crow, M.Sc., Ph.D. 
Introduction. 
Tnu material which is reported upon in the following pages was 
collected by Prof. F. E. Fritsch in Ceylon, Aug. 21-Nov. 10, 1903, 
and forms part of a larger collection. It was handed to me for in¬ 
vestigation early in 1919, and for some months the work was carried 
out under the supervision of Prof. Fritsch, to whom I am greatly 
indebted both for advice on several doubtful points, and for allowing 
me free access at all times to his magnificent collection of figures. 
I must also acknowledge the help of a Government grant, made by 
the Committee of the Privy Council for Scientific and Industrial 
Research. 
The general characters of the Cyanophycean and Chlorophycean 
Flora of Ceylon have already been dealt with bv Fritsch in a paper 
<p roc. Roy. Soc. B. lxxix.) in which, however, a consideration of the 
plankton was not included. The systematy of the freshwater algal 
flora forms the subject of a small contribution by Lemmermann 
in Zool. Jahrb. xxv. and an extensive list by W. & G. S. West in 
Trans. Linn. Soc. B. Ser. 2, vi., the latter not dealing with the 
plankton species. The collection dealt with here consists mainly of 
Plankton. Much of it is from the so-called “tanks”—large reservoirs 
of artificial origin in which, however, the algal flora lives under prac¬ 
tically natural conditions. Most of the collecting was made from 
the shore by means of a plankton net. Apart from this normally 
littoral forms in some cases may have been carried out as tycholim- 
netic plankton, and have thus been included. The material is pre¬ 
served in tubes of dilute formaldehyde, and for the most part the 
specimens are in an excellent state of preservation. 
