448 My. J. W. Davis on a new 
Australia by the north while the continent was being upheaved 
and its climate still humid, and to have become differentiated 
since the entire drying up of the interior sea so desiccated the 
country as once more to isolate West Australia almost as 
effectually as if it were surrounded by water. But Mr. 
Wallace does not make this sufficiently clear. When, how- 
ever, we come to that part of Mr. Wallace’s hypothesis which 
deals with the connexion between Australia and New Zealand 
we find it to be not so satisfactory. In the first place, the 
facts of geology are against any connexion having taken 
place between the two countries at the time supposed. In 
the second place, the South-American element in the fauna 
and flora is not separated from the Antarcticelement. In the 
third place, the hypothesis fails to expla the South-A merican 
element, except on the supposition of large extensions of land 
during the warm Miocene period, for which there is no suffi- 
cient evidence, and which if it had oecurred would have 
allowed birds as well as frogs and land-shells to pass. And 
in the fourth place, it ignores altogether the special relation 
which exists between New Zealand and some of the islands 
in the Pacific. The hypothesis here proposed is no doubt 
incomplete, and will be much improved when the paleon- 
tology of New Zealand is better known; but it does, [ think, 
give a fairly satisfactory account of the origin of the South- 
American, Australian, and Polynesian elements in our fauna 
and flora. The Antarctic and North-Temperate elements still 
remain for consideration; but so wide a subject cannot be 
entered upon at the end of an address, and I must postpone 
all discussions to some future occasion. 
XLIX.—Deseription of a new Genus of Fossil Fishes from 
the Lias. By James W. Davis, F.G.S. &e. 
[Plate XVI] 
Genus LissoLepis, Davis. 
Class Pisces. Subclass PaLarcuTuyrs. Order GANorDeEt. 
Suborder ACIPENSEROIDEL Family Patzoniscip zm. 
Body fusiform; head large; gape wide; jaws elongated, 
furnished with closely-set uniform enamel-tipped teeth ; scales 
of medium size, rhomboidal, mostly with smooth surface, a few 
anterior ones with slight furrows, posterior margin serrated ; 
