BY C. HEDLEY. 507 



The existence of this genus in Australasia was first announced 

 by R. M. Johnston, who in March, 1877, laid before the Royal 

 Society of Tasmania an account of G. petterdi, from the vicinity 

 of Launceston 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. Tasmania, 1888, p. 84, but which Mr. Johnston, 

 perhaps critically, omitted to number or explain, are drawings 

 2a, 2b, 2c, presumably of this species. Appended to this paper 

 is a table in which, under " General Remarks," a Gundlachia 

 heddomei is mentioned as described "since 1881" by Petterd, 

 which form is asserted to be " undistinguishable from Guyidlachia 

 petterdir 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 mollusc by W. F. Petterd, dated Nov., 1883, and evi- 

 dently 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 honour 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 fluviatile 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. 

 Ampkijjeplea, Pota7nopyrgus, and Gundlachia are confined to Tas- 

 mania 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 Potamojjyrgus, Gundlachia, and, according 



