64 THE JSAUTILUS. 



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 Conehnlogy contains, in Vol. iv, p. 150, a 

 notice of a new and nameless mollusc 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 (Jouru. of Conch., i, p. 399), Fischer 

 (Manuel, p. 251), Tate (Rep. Austr. Assoc. Adv. Sci., 1887, p. 325), 

 Spencer (oj>. fit. 1<S!>2, p. 96), and Suter (N. Z. Journ. Sci. iii, p. 252) 

 have each commented thereon. The fiuviatile molluscs, 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, Potamopyrgu-s and Gundlachia are confined to Tasmania and 

 to the south-east fringe of Australia ; they all reappear in New 

 Zealand, but the Viripara and Melanin characteristic of tropical 

 and subtropical Australia have failed to accompany them there. 

 The extension of Potamopyrgus, Gundlachia, and, according to Tate, 

 perhaps Amnicohi, 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 I'oh' from Tasmania to Tierra del Fuego, would have afforded a 



