2 F. E. PRITSCH. 
species in common, and the representation of the main groups is rather different. The 
collections made by the members of Sir E. Shackleton’s Expedition, on the other 
hand, come from very much the same region as those which form the subject of the 
present communication, and there is a considerable degree of resemblance between 
them, a fact which is especially noticeable as regards the Diatoms. Owing to the 
very appreciable delay * which has taken place in the preparation of this report, 
Messrs. West’s report on the freshwater Aloe of Sir E. Shackleton’s Expedition has 
appeared since this manuscript left my hands. Professor G. 8. West was good enough 
to forward to me in the summer diagnoses and figures of the new forms found by him 
and his father, and for the last two months a proof of their paper has been in my hands. 
Tam glad to have this opportunity of thanking Professor West for his courtesy, which 
has to some extent relieved the great labour of working out the collections. 
A considerable number of species and varieties are common to the two 
collections, and these include several of the new forms described by Messrs. West. 
Nevertheless the present report brings a considerable number of new records and the 
descriptions of sixteen new species and five new varieties. We may evidently look to the 
Antarctic continent to furnish us with quite a large number of new representatives 
of previously known genera, although thus far no new generat have come to light. 
This is rather surprising, as the extreme conditions under which the algal flora of the 
Antarctic exists might be expected to lead to the development of new types. 
The distribution of @enera and species in the different croups is as follows : 
(=) to) 
Genera. Species. 
Tsokontie ‘ ; ; : (} : , d 13 
Sonjugatss . : : is ; : 1 
Cyanophycee . : : ae walle : : 52 
Diatomacex . : : eo ae lclua. : : : 25 
Totals . ‘ a) BSc . : ; 91 
The prevalence of Cyanophyceous forms and Diatoms, which this table discloses, 
is true also of the number of individuals. It does not appear that any green Algee 
are common in the freshwater flora of the Antarctic, except for species of Prasiola, 
which have long been recognised as important constituents of the flora of these 
regions, and species of Pleurococeus or allied genera. Species of Chlamydomonadacez 
also appear in abundance, but their occurrence is probably rather local. On the 
other hand numerous Protococeales that are prevalent in the waters of other parts 
of the earth are completely wanting, the filamentous Chlorophyceze are represented 
only by Ulothria, and the whole host of the Conjugatee are as good as absent. The 
discovery of a few individuals of a Desmid (c¢/. pp. 20-21) is of great interest in this 
* For this delay the author is alone responsible, although largely due to circumstances which were beyond 
his control, 
+ A new genus was described among the Alge of the South Orkneys (op. cit., p. 304), but this came from the 
yellow snow flora, a type of algal flora that was previously unknown. 
