72 CONTRIBUTIONS FOR SYSTEMATIC CATALOGUE AQUATIC SHELLS. 



Plate IV. Vis. 3. 



Badifcif.— South Esk Eiver. 



In the First Basin near Launceston this species is in extreme 

 profusion both in swiftly running and almost still water. Ou 

 the large boulders of diorite it may be seen in countless 

 thousands in company with one or two other small forms. In 

 coloration it is subject to considerable variation, sometimes 

 the edge of the aperture is almost white, and much resembles 

 the tint of the rock to which they adhere. In this 

 locality it appears to take the place of /*. f/igra, a species that 

 is not found with it. The arrangement of the denticles ou 

 the radula shows all the essential characteristics of the genus 

 in which I havu placed it, and their form differs so very 

 materially from those of the last described, that no doubt can 

 exist as to their specific difference. 



POTAMOPYEGUS SmITHII. n. Sp. 



Plate I. Fig. 10. 



Shell, very minute, subpupiform, brownish horn, glossy, 

 almost smooth. Whorls, 5 to 6, very convex, suture much 

 impressed, body-whorl moderate size. Aperture, ovate 

 pointed above, straight, peristome continuous, free, labrum 

 thin, not expanded. Operculuvi, thin, horny, paucispiral. 

 Length 2 ; breadth 1 mill. 



Hahitdt — Heazlewood, Arthur, Waratah, and Castray rivers, 

 abundant on stones, etc. 



This little si)ecies has somewhat the appearance of 

 Amnicola Simsoniana, Brazier (Plate II., fig. 5), but differs in 

 its much smaller size and more swollen whorls ; it may, 

 however, prove to be an extreme variation. So far it has 

 only been obtained iu the western streams of the island, 

 where it no doubt has a wide range. I have named it after 

 Mr. James Smith, the veteran explorer and discoverer of the 

 Mount Bischoff Tin Mine. 



POTAMOPYEGUS BeOWNII. 11. Sp. 



Plate III. Fig. 14. 



Shell, minute, turbinately conical, thin, greeni.sh brown, 

 dull, c'jvcrc'd with a thin cpidermiH. Whorls, 5, rounded, 

 suture deep, spire somewhat short and small, obtuse. 

 Aperture, ovate, distinct, labrum thin. Operculum, horny, 

 pancisj)iral. 



Length, 2 ; hrcadlh, l.[ mill. 



Habitat— at. Paul's River, near Avoca (Mr. J. Brown), 

 Scamandcr and Styx rivers, George's Bay, St. Mary's (Mr. A. 

 Simpson). This shell has no important specific character 



