25 



sub-genus Amnicola. Woodward makes it a sub-genus of 

 Melania, wliile in Clienu's work it is referred to Pahidina. 

 From examination under the microscope I find that the 

 muzlzle tentaculse and foot more closely resemble Pahidina ; 

 while the long, narrow, linear band (twice as long as in any 

 of the genus Bithynella) of 120 rows of 3 — 1 — 3 denticulated 

 teeth, relates it more closely to Melania. The eyes, however, 

 are sessile on the outer base of tentacles, which, as well as 

 the transversely wrinkled and j^i'ojected muzzle, are tinged 

 more or less with dark blue, as in B. unicarinata (Tenison- 

 Woods). The shape of shell closely imitates the genus 

 AmfpuUaria, but the animal has not the tentacular muzzle, 

 the shortly-stalked eyes, nor the shelly opercukun of that 

 genus. In many resj^ects it apj^roaches the genus Valvata ; 

 but as the aperture of shell is considerably modified by last 

 whorl, I think the reference to Amnicola to be most suitable. 



Ancylus Woodsii. n. s. 



Shell small, oblong, ovate, white, transparent, depressedly 

 obliquely conical ; concave posteriorly, convex anteriorly, 

 apex subcentral, concentrically striate and crossed by faint 

 distant radiating lirse ; ej^idermis not visible or absent, surface 

 dotted with very minute transparent bluish-white egg-like 

 bodies. Long. 2| — 3, lat. 2, height |. Animal and teeth 

 almost similar to ~Gundlacliia Peitevdi. Habitat — South Esk \ 

 Meander, Deloraine ; Avoca, Laimceston ; common on the 

 submerged living leaves of Triglochin. 



A very minute shell, and distinct from the other two- 

 described species, easily recognised by its size, flatness, and 

 apex position. 



Var. A. Shell larger than the above, ]3ale horny, rounded 

 on side most distant from apex. Long. 5|, lat. 3, height 2. 

 Isolated pool, St. Leonards ; periodically connected with 

 North Esk flood waters. 



Var. B. Shell narrowly oblong, pale horn, apex more 

 elevated than ordinary type. Long. 3|, lat. 2, height 1. 

 Pool, St. Leonards. 



Var. Y. Shell more solid, with black epidermis. Long. 

 PJ, lat. 2, height 1. Hobart Town. Mr. Petterd. 



Ancylus Tasmaxicus. (Tenison- Woods.) 



Var. A. Thin pale honi. 1st Basin, Launceston. 



Bithynella nitida. n. s. 



Shell small, elongate jDyramidal, somewhat solid, pale flesh 

 color, shining; spire acute; whorls 6, rounded; aperture 

 ovate ; peristome continuous ; margin very slightly thickened 

 and reflexed, free from body whorl. Long. 3, lat. If — 2. 

 Fossil, Thunder and Lightning Bay, Barren Island. 



