106 SUNKLANDS OF PORT PHILLIP BAY AND BASS STRAIT 
The Bassian Fauna and Flora 
The Bassian fauna and flora comprised the animal and plant 
life that formerly existed on the land surfaces between the 
mainland and Tasmania, and which migrated to what are now the 
Bass Strait Islands and Tasmania from the mainland. Spencer 
(1893) drew attention to the close alliance existing between the 
zoological groups of Tasmania and that part of Victoria south 
of the Dividing Range. 
The present discussion of the fauna and flora is restricted to 
certain genera and species, both living and extinct, the ecology 
of which throws some light on the physical aspects of the land 
surfaces. The most informative are the land shells, freshwater 
shells, the earth-worms, and the mammalia, some of which are 
represented by fossil prototypes: important evidence is also 
forthcoming from other groups that are assumed to have existed 
on the land bridges. 
Land shells are mainly vegetable feeders on plants, cryptogamic 
vegetation, decaying vegetation, etc. The vegetable nature of their 
food, and their preference for moist conditions, explains their 
prevalence in warm humid regions, particularly on islands; in 
hot and desert regions they appear only during the rainy seasons, 
or times of heavy dews. Some species of Bothriembyron bury 
themselves in the mud of swamps when they dry up. On the other 
hand Ilelicarion is found mostly in cold and temperate regions, 
or, if in the areas with warmer climate, in the cooler mountain 
tracts. 
Of the land shells from Victoria listed and described by Gabriel 
(1930) and found in the Bass Strait Islands or Tasmania, the 
recorded habitats of only 6 per cent are on the northern drainage 
fall in Victoria and, excluding the widespread Succinea australis, 
(Ferr.) less than 3 per cent. ; the rest were collected on the damper 
southern fall or the water-shed. Of the eleven species found on 
the Bass Strait Islands, seven — Gharopa albanensis (Cox), C. 
diemenensis (Cox), Ilelicarion cuvieri (Ferr.), Laoma minima 
(Cox), L. penolensis (Cox), Bhytida ruga (Cox) and Succinea 
australis (Ferr.) are conunon to both Victoria and Tasmania; 
two — Garyodes dufresni (Leach) and Bothriembyron gunnii 
(Sow.) to the Islands and Tasmania; and one — Ghloritis victoriae 
(Cox) to King Island and Victoria. May (1923) states that as 
far as the species G. victoriae is concerned, “its appearance seems 
to suggest the necessity of land communication with Victoria at 
some period, as this species occurs in that State but not in Tas- 
mania.” It is found in Victoria on the southern fall, and outside 
Victoria its mainland habitat is restricted to Mount Kosciusko. 
