Microscopical Society of Victoria. 
15 
On the Hydroida of South-Eastern Australia , with Descriptions of 
Supposed New Species , and Notes on the Genus Aglaoplienia. 
By W. M. Bale. 
(Read 30tli .Tune, 1881.) 
The South-Eastern portion of Australia possesses a liydroid 
fauna, differing so much from that of any other region as to have 
induced Professor Allman, when dealing with the general distri¬ 
bution of the order, to rank it as a distinct province. At the 
time of the publication of the “ Monograph of the Gymnoblastic 
Hydroids,” in which his remarks on distribution occur, only a 
small number of species liad been recorded as common to this 
province, and any other part of the world ; and these consisted 
principally of two or three widely-distributed forms, such as 
Sertularia operculata ; but several have since been added to the 
list, most of which occur in Australia and New Zealand. So far 
as I am aware, not a single species is known to be common to the 
north and south coasts of Australia, but this may be owing, in 
some measure, to the want of fuller investigation, especially among 
the smaller members of the order. 
Though the profusion in which some zoophytes are cast on the 
British coasts, as depicted by Mr. Hincks and other authors, 
is almost without parallel in this country, and few of our 
species usually occur in large quantities, our seas are by no means 
deficient in number and variety of forms, as compared with those 
of Britain. In Mr. ITincks’s “British Hydroid Zoophytes” ther 
are described about twenty-four species of Sertulariidce , and 
fourteen of Plumulariidce; while from South-Eastern Australia 
and Tasmania there are already recorded, of the same two families 
respectively, at least thirty-six and twenty-one species, including 
those in the present paper, and I have recently obtained four or five 
additional ones, while doubtless many still remain to be discovered. 
A number of Australian Species are included in the works of 
Lamouroux, Lamarck, and others of the older naturalists, but as 
it is, in most cases, impossible to identify them with any certainty, 
owing to the insufficiency of their descriptions, and as it is not 
usually stated whether they occur on the north or south coasts, I 
have not taken them into account; neither have I included eight 
or nine species of Kirchenpauer’s, which are merely described as 
