44 DR. G. S. WEST ON THE ALGÆ OF 
The latest contribution to our knowledge of Australian Alge is a paper 
by Playfair on Desmids from New South Wales *. This paper is unfortu- 
nately too reminiscent of W. B. Turners “ Fresh-water Algze of East 
India” f. It affords a marked contrast to the careful work of Nordstedt. 
exhibiting a want of experience of the family dealt with f. — Especially is 
this the case in the suggestions for grouping well-marked types under one 
species and in the founding of other species on the most trivial characters. 
There is likewise an inexactitude in the figures which is but too common 
among the students of this group of Ао». Judging by his continual 
references to “immature forms,” Mr. Playfair seems to have rather curious 
ideas on the growth of Desmids. He appears to imagine that a Desmid may 
change its form, or develop spines or warts, at any time during its existence, 
losing sight of the fact that, unless dealing with monstrosities, at least one 
semicell of any Desmid must be mature. Cell-division, except under abnormal 
cireumstances, does not take place until the two halves of a Desmid are 
equally developed, the newer half having arrived at maturity. Consequently, 
in any Пезт in which the two semicells are exactly alike, growth has ceased, 
and that individual is mature & Further alteration of form, excluding the 
possibility of changes caused by the attacks of parasites, does not take 
place after the completion of the development of the new half, and spines 
once formed cannot become bifid or trifid, or in some other way change their 
nature, as Mr. Playfair appears to imagine. Neither do monstrosities appear 
to be particularly common in Australia. I have examined large numbers of 
Australian. Desmids, and. cell-division amongst this family appears to take 
place in Australia much as it does elsewhere, the new semicells arriving at 
maturity with but slight variation from the old ones. 
The works which have just been cited, together with the present inves- 
tigation, although dealing with very limited and somewhat remote parts of 
the Australian continent, yet enable one to form а general idea of the Alga- 
flora of Eastern Australia. They are also sufficient to show that among the 
more cosmopolitan forms there are a number of types peculiar to Australia 
and New Zealand. These are specially considered in a succeeding chapter. 
* (1. J, Playfair, “Some new and little-known Desmids found in New South Wales.” 
Proc. Linn. Soc. №. S. Wales, xxxii. part 1 (1907), pp. 160-200, t. 2-5. 
t W. B. Turner in Kongl. Sv, Vet.-Akad. Handl. xxv. по. 5 (1893). 
| Mr, Playfair describes under the name of “ Closterium Cancer, sp. n." either а species 
of the Protococeaceous genus Zteinschiella ог a vesting-cyst of one of the Peridiniales ; his 
description and figure are insufficient to determine the point. Under the name of * Closterium 
naviculoideum, sp. п.” he appears to have described one of the common attenuated Dintoms 
of the genus Nitzschia, presumably Nitzschia acicularis. lle also states that another Species 
of Closterium (© С. calamus, sp, n.") possesses parietal chloroplasts, whereas his figure clearly 
shows the usual axile ridged chloroplasts of Closterium with a central row of pyrenoids, 
§ The only exceptions to this are those few species of Closterium and Penium which 
develop a *girdle-band." This is а cylindrical piece of cell-wall intercalated between the 
new and the old half-eells, and resulting from a growth to maturity subsequent to the 
completion of cell-division, 
