102 



descriptions of some 



New Species of South Australian 

 pulmonifera. 



By Professor Ralph Tate, A.L.S., F.G-.S., &c, President. 

 [Read July 6, 1880.] 



Ancylus Australicus, spec. nov. Plate iv., figs. 4a— 46. 



Shell pale, thin, and delicate ; conic depressed, lengthened ; 

 sides subrectilinear or slightly convex, diverging slightly 

 forwards. Apex blunt post-median, with about two-fifths the 

 shell behind it, inclining backwards, and directed towards the 

 right ; the line from the apex to posterior border slightly 

 concave, to the anterior border almost rectilinear. Peritreme 

 oval, distinctly narrowed posteriorly. 



Dimensions of a moderately large example ; length, one-sixth 

 of an inch ; breadth, one- tenth of an inch ; height, one- 

 seventeenth of an inch, the respective dimensions being in 

 the ratio of 100, 60, and 35. 



The newly-formed shell is of a pale horn colour, but older 

 parts have a reddish to blackish-brown coloured epidermis. 

 The anterior portion of the cone is ornamented with strong 

 concentric folds. 



The foot of the animal is translucent, white, and is obtusely 

 rounded behind. The tentacles are translucent, white, tri- 

 angular, and subcompressed at the base, but are cylindrical in 

 the upper part, ending in a blunt tip. The eyes are black, and 

 in front of and slightly interior to the bases of the tentacles. 

 The muzzle is emarginate, when extended. Only the tips of 

 the tentacles are visible from beneath the shell when the 

 animal is gliding. 



Habitat and Station. — This species was first made known to 

 me by Mr. Stirling Smeaton, B.A., who collected one example 

 in a stream at Lyndoch Yalley. I have since found it on the 

 under side of the floating leaves of Triglochin procera in the 

 Reedbeds ; and abundantly in the River Torrens at Adelaide, 

 on the under side of stones and on the submerged leaves of 

 aquatic plants. Mr. Bednall informs me that he collected it in 

 1876 in the Brownhill and Waterfall Gully Creeks. 



