144 THE NAUTILUS. 



upper part of the basal whorl ; width of umbilicus about one-fifth 

 greater diameter of shell. 



Numerous dark microscopical lines extend from the peristome over 

 the body whorl nearly perpendicular to the lines of growth. 



Greatest diam. 17, least diam. 14, alt. 9 mm. 



Locality, San Jacinto Mts., California. 



A NEW N.-E. AUSTRALIAN AMNICOLOID. 



BY HENRY A. PIUSBRY. 



The species described below was received from Mr. D. Thaanum. 

 It is evidently referable to the genus Petterdiella, the synonymy of 

 which is as follows : 



Ampullaria sp., Tenison- Woods, Proc. Roy. Soc. Tasmania 1876, 

 p. 117. 



Amnicola sp. of various authors. 



Brazieria Petterd, Proc. Roy. Soc. Tasm. 1888, p. 76. Not 

 Brazieria Ancey, 1887 (see Man. Conch. IX, p. 29). 



Petterdiana Brazier, Proc. Roy. Soc. Tasm. 1896, p. 105. 



Pseudampidlaria Ancey, Ann. Mus. d'Hist. Nat. Marseille I, 1898, 

 p. 148. 



All of the above names are based upon Ampidlaria tas?nanica Ten.- 

 "VVoods. 



Petterdiana Thaanumi n. sp. 



Shell small, globose, Amputtaria-shaped, narrowly perforate; light 

 brown; smooth except for slight growth-lines. Spire short. Whorls 

 4, quite convex, the last perceptibly flattened below the suture, 

 globose, not angular at the periphery; narrowly excavated around 

 the perforation. Aperture oblique, roundly ovate, narrowly rounded 

 above ; outer lip simple ; columella concave, wide and flattened ; 

 parietal callus short and rather heavy, though very much less thick 

 than in P. tasmanica. Alt. 3.3, diam. 2.8 mm. 



Near Cairns, Queensland, Australia. 



This species differs from P. tasmanica in having the last whorl 

 much less dilated towards the aperture, this difference being particu- 

 larly noticeable when the shell is viewed in the line of the axis from 

 above ; the aperture is consequently less ample, and the outline of 

 the shell in a front view is more regular. There is also a fraction of 

 a whorl more than in P. tasmanica, the columella is not so wide, and 

 the callus across the parietal margin is comparatively thinner, while 

 in P. tasmanica the heavy columellar callus continues across the 

 parietal wall. 



This is the second species of the genus, and so far as I know the 

 first to be recorded from Australia. 



