PJ.A, NAT.. 
\0L. XVIII.. No. 3. 
FU’VIFArxrL.NE OF ArKTEALIA. 
67. 
Lessonian Fluvifaunula. 
The LESSONIAN FLIATFAUNULA is restricted to the 
rivers of Eastern New South \\'aleSj \ ictoria, and North Tas- 
mania, and includes Austrocobitis (Jollytail), Retropinva (Trout- 
lets), Potaynolosa (Freshwater Herring), Trachystoma (Fresh- 
water Mullet), Bullrout [N otesthes) and Pseudoynugil (Blue- 
eyes). Eels are well distributed, the dominant form being Air 
guilla australis. 
d’he molluscs are remarkable for the development of the 
freshwater Mussels, four genera being peculiar, Ilyridunio, Rugos- 
iryria^ Propehyridella and Protohyridella, the first-named being 
also recorded from the Mitchelllan sector. The Bullinidae is 
also well represented bv numerous species whose affinities are 
not well understood, the Sturtian Jsidorella also wandering 
through the Mitchellian into this faunula. 
Tobinian Fluvifaunula. 
The TOBINIAN FLIATFAUNULA Is known only from 
the Southern portion of the Maugean Sub-Area and is distinguish- 
ed by the peculiar Troutlet, Lovettia, while Lamprey occur in this 
fluvifaunula, also entering the Mitchellian, while one genus 
{Geotrm) even extends to the Vlaminghian fluvifaunula. Retro- 
pinna tasmanica is a southern outlier of a Lessonian group. Neg- 
atively, among the Mollusca, Mussels are entirely missing, while 
(Neo/.elanic) Potamopyrgids flourish: the extraordinarv fresh- 
water limpet, Legrandia (— Tasmancyliis) distinguishes this 
fluvifaunula absolutely. 
Krefftian Fluvifaunula. 
The KREFFTIAN FLUXdFAUNULA is comparable with 
the land faunula of the Oxle\'an Sub-Area, practicallv occupying 
that region; the characteristic Lungflsh, N eoceratodus,, being 
otlierwise unknown throughout Australia. Among the molluscs 
a similarly unique Mussel, Cuannerunio, and a \ iviparine genus 
Larina, have no known relations. 
Jardinean Fluvifaunula. 
Northwards, the JARDINEAN FLU\ IFAUNULA, corres- 
ponding with the d’orresian faunula of the Solanderian Sub-Area, 
is very little known, a Sunfish {Rhadinocentrus) and representa- 
tive forms of the Lessonian GlosSamia (gillii), Craterocephalus, 
Alelanotaeniidae and Pseiidomugil are on record. The eel, An- 
guilla reinhardtu, is alone found though is extends southward into 
the Lessonian sector. Among the freshwater Mussels, Rugos- 
hyria aquilonalis may be characteristic, as also Jardinella (type, 
Petterdiana thaanumi Pilsbry), a small globose freshwater Ris- 
soid, of unknown relationship. 
