322 JOURNAL OF SCIENCE. 
ABSTRACT OF PAPER ON DESMIDIE: 
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Read at Meeting of Canterbury Institute, October 5, 1882. 
The introductory remarks contain acknowledgements of in- 
debtedness to Dr. Spencer, of Napier (from whom several of the 
plants described have come), to Mr. Joshua, F.L.S., of Cirencester, 
England, and to Professor Nordstedt, of Lund, Sweden, who have 
sent tothe author various European Desmidiezeand papersthereon. 
Also a statement of the system of measurements adopted in the 
paper, the basis of which is one ph=1-1000th millimetre=about 
1-25000th inch. This system, first proposed by continental 
microscopists, is gradually gaining ground in England as being 
intelligible to observers of all nations. In the journal of the 
Royal Microscopical Society, there is inserted every few: months 
a series of tables showing the conversion of English inches and 
foreign fractions of metres into » and probably in a few years 
the system will be universally adopted. 
The paper itself consists of two parts. Part I contains the 
description of all the species of Desmidieze which have come 
under the notice of the author since his first paper in 1880, 
whether new species or identical with European plants. In this 
part all the plants received from Napier, if they had not been 
previously observed by the author in Canterbury, are marked 
with the distinguishing letter S. 
The conjugation of Desmidiez has been observed since 1880 
in some half-a-dozen species, but for some reason or other this 
process seems to be much more rare here than in England. Even 
' when seen here, except on two occasions, in the case of Closter- 
num acerosum and Pentium margaritaceum, conjugation occurred 
only in detached specimens; in those two plants gatherings 
were made of large masses of conjugating fronds. 
Only two of the Desmids described appear to be new species, 
but several are believed to be new varieties. The following list 
contains all those described in Part I. as probably new, exclusive, 
that is, of European plants :— 
Cosmarium valfsi, var. B, var, nov.—Distinguished by its 
minute size, which is quite constant. Length 37°5 pn. 
Cosmarium obsoletum, Hantzsch, var. punctatum ; var. nov. 
The original plant is very rare in Europe, and occurs also very 
sparingly (teste Nordstedt) in the Sandwich Islands. It is dis- 
tinguished by short awns at the entrance of the constriction. 
The present variety differs in having distinct puncta. Diameter 
60 p 
Cosmarium speciosum, Nordstedt, var. inflatum ; var. nov.—Very 
small, and prettily marked with vadiating gemmules, producing 
a grooved effect. The new variety differs in having a prominent 
inflation on each segment. Length 72 p. 
