BY HENRY TRYON. 19 
the subject of these remarks which he met with in the estuary of 
the Murray. (Nature, 1878; vol. xviii., No. 444, pg. 11. 
Beyond the Australian seas this sea sawdust* or whale’s 
spawn, as it has been popularly named, has been observed at 
numerous localities throughout the Pacific and Atlantic Oceans, 
sometimes covering interruptedly large areas of several hundred 
miles in extent. 
On closer observation its particular state is very evident, and 
when slightly magnified it presents a “chopped hay”’ appearance, 
and when more so all the characters by which T’richodesmium—a 
genus belonging to a spurious group of minute algaw—has been 
defined, are very manifest. 
The occurrence of this genus in Moreton Bay is on other 
grounds more than probable, since this very evident odour 
under the appearances described is shared by the Trichodesmium 
of authors; and, moreover, although Trichodesmium is not men- 
_tioned by Dr. Turner in his “‘ Phycologia Australis,” it is recorded 
by Otto Sonder from north and tropical east Australia. [Algee 
Australiane Hactenus Cognite, Hamburg, 1880. Miiller’s 
Fragm. Phyt. Aust. vol. vi., Sup. p. 42.] 
Trichodesmium,+ a genus founded by Ehrenberg for a single 
species T. erythreum, includes those minute algw of the 
group Nostocacee which are composed of regular microscopic 
* M. Evenor Dupont, in allusion to a similar phenomenon in the Red 
Sea, writes :—“ La sciure d’ un bois de cette couleur de l’accajou par 
example produirait 4 peu prés le méme effet.”’—Comptes Rendus, 1844; 
Wolls sabes, Tlyale 
+ Montagne gives the following definitions of the genus and species: 
—“ Fila libera membranacea, tranquilla, simplicia, septata, fasciculata, 
fasciculis discretis, muco obvolutis. Algz sociales rubro sanguines, 
demum virides, superficiei maris immenso gregeinnatantes. Char. Spec. 
Trichodesmium erythreum, Ehrenb. Filis libere natantibus mem- 
branaceis ancipitibus: in fasciculos minutos fusiformes et muco involutos 
Paralleliter conjunctis, articulis diametro subduplo brevioribus, eeniculis 
zqualibus constrictis aut extantibus.”—Comptes Rendus, 1844; vol. xaiKe 
pe LL. 
