64 THE NAUTILUS. 
ton in North Tasmania. In the first of two plates attached to 
“ Critical Observations on Recent Contributions to our Knowledge 
of the Fresh-Water Shells of Tasmania,” Pt.i, Proc. Roy. Soc. Tas- 
mania, 1888, p. 84, but which Mr. Johnston, perhaps critically omit- 
ted to number or explain, are drawings 2a, 2b, 2c, presumably of this 
species. Appended to this paper is a table in which, under “ Gen- 
eral Remarks,” a Gundlachia beddomei is mentioned as described 
“since 1881” by Petterd, which form is asserted to be “ undistin- 
guishable from Gundlachia petterdi.” I believe that I am correct 
in stating that no species has ever been described under this title. 
The Quarterly Journal of Conchology contains, in Vol. iv, p. 150, a 
notice of a new and nameless molluse by W. F. Petterd, dated Nov., 
1883, and evidently relating to the form written of by Johnston. 
Prof. Tate recorded (Proc. Roy. Soc. Tasmania, 1884, p. 216) G. 
petterdi from the hill streams of the Mount Lofty Ranges near 
Adelaide. 
Finally, in a paper I have had the honor of communicating to 
you this evening, Suter declares the existence of an undetermined 
and probably new species from New Zealand. 
The broken range of Gundlachia has attracted the attention of 
several conchologists: Petterd (Journ. of Conch., i, p. 399), Fischer 
(Manuel, p. 251), Tate (Rep. Austr. Assoc. Adv. Sci., 1887, p. 325), 
Spencer (op. cit. 1892, p. 96), and Suter (N. Z. Journ. Sci. iii, p. 252) 
have each commented thereon. The fluyiatile mollusca of Southern 
Australia have, strange to say, a stronger likeness to those of New 
Zealand than to those of the northern part of this continent.. Amphi- 
peplea, Potamopyrgus and Gundlachia are confined to Tasmania and 
to the south-east fringe of Australia; they all reappear in New 
Zealand, but the Vivipara and Melania characteristic of tropical 
and subtropical Australia have failed to accompany them there. 
The extension of Potamopyrgus, Gundlachia, and, according to Tate, 
perhaps Amnicola, with another Australian genus, Mycetopus, to 
America is even more remarkable. 
To explain similar instances, Mr. H. O. Forbes (to whose courtesy 
I am indebted for a copy of this very interesting paper) has lately 
revived the theory of an Antarctic continent, and supports it by 
several weighty arguments, notably the presence in the Patagonian 
Eocene of marsupial remains nearest allied to those now existing in 
Australia. A strip of land, with a mild climate, extending across 
the Pole from Tasmania to Tierra del Fuego, would have afforded a 
