OF SOUTH AUSTRALIA. 
123 
the procarp, generally with direct connection between carpo- 
gonium and the auxiliary cells. 
(2) The Platoma Type.— A normal intercalary cell of the mother- 
plant serves as an auxiliary cell. This type is characteristic of 
the order Gigartinales, in which the fertilized carpogonium 
becomes connected to the auxiliary cell in a manner identical 
with that in the order Cryptonemiales. Examples of the simpler 
types in this order are Platoma, Furcellaria, Agardhiella, and 
Rhabdonia, and of the higher types in which a procarp is formed 
Cystoclonium , Calliblepharis, Hypnea , Phyllophora, and Gigar- 
tina. 
(3) The Rhodymenia Type. — The auxiliary cell is already cut off from 
a daughter cell of the supporting cell prior to fertilization. This 
type is characteristic of the order Rhodymeniales, in which the 
carpogonium and auxiliary cell always form a unit, the procarp, 
with direct connection between the two. 
(4) The Ceramium Type. — The auxiliary cell is cut off from the sup- 
porting cell of the carpogonial branch after fertilzation. This 
type is typical of the order Ceramiales, in which procarps are 
always formed, but in a few of the more primitive species con- 
nection may not be direct but through a short one-celled or 
sometimes two-celled connecting filament, e.g as in Anti- 
thamnion, Callithamnion, Spermothamnion , and Dasya. For the 
more advanced types forming the procarp, see the life-cycle of 
Polysiphoma. 
The Classification of the Red Algae. 
From an examination of the life-cycle of Polysiphonia it may be seen that 
the one species produces three sorts of mature thalli in regular succession, 
and unless fruiting, these are morphologically indistinguishable. However, 
some algae are homothallic, i.e. f they bear both male and female organs on 
the same thallus, and in some species the generation bearing tetraspores is 
unknown. Kylin and his associates have attempted to classify the Red 
Algae upon a phylogenetic basis, and to do this they have shown that it is 
necessary to take into account the manner in which the gonimoblast 
develops and obtains its nutritional requirements. Such facts as these are 
not readily ascertained without exact cytological studies, often upon plants 
grown in artificial culture media, and these require the facilities of a well- 
equipped botanical laboratory, and while this may be available to the pure 
taxonomist, it is of little help for the field worker. As the majority of the 
early phycologists were essentially collectors, their early classifications 
reflect this viewpoint upon the group and were in the main essentially 
morphological classifications. However, as any botanist soon becomes aware, 
a classification based purely upon vegetative structures ceases to be a natural 
one, and is also very prone to error due to variations from plant to plant 
reflecting environmental conditions. Among the Red Algae there is such 
