53 



Planorbis Essingtonensis, E. A. Smith. 

 Bef.—Froc. Lin. Soc, vol. xv., p. 294, t. 6, figs. 33-35. 

 Habitat. — Eresliwater lagoons, Point Smith, near Port 

 Essington {Brit. Mm.) ; on submerged plants, Eiver Adelaide 



(E.T,). 



Planorbis meniscoides, spec. nov. 



Shell shining, pellucid, yellow-horn colour, with a sunken 

 spire, and flattened base ; umbilicus deep and narrow. Last 

 whorl obliquely convex above the angulated periphery. 

 Whorls four, convex, separated by a deep suture. Surface 

 marked by strong sigmoidal striae and folds of growth coinci- 

 dent with the outline of the margin of the aperture, which is 

 very oblique. 



This species resembles Segmentina Victorice, Smith, Proc. Lin. 

 Soc, 1882, p. 296, pi. 7, figs. 11-13, from which it differs by its 

 smaller umbilicus, flatter base, and less convexity of the upper 

 surface. 



Greatest diameter, 4*5 millim. ; smallest diameter, 4, nearly ; 

 height, 1-5. 



Hah. — Buffalo Swamp, Port Darwin (coll. Mr. Brazier). 



Ancylus australicus, Tate. 



Bef.—Trans. Boy. Soc. S. Aust., vol. iii., p. 102, t. 4, f. 4, 

 1880 ; id. Smith, F.L.S., t. 7, figs. 36-37, 1882. 



Hah. — Eiver Adelaide ; a single specimen, but lost before 

 comparison with type examples (E. T.). The two examples 

 of an Ancylus in the British Museum from Comet Creek, 

 Queensland (Leichardt Exped., 1844) seem to be correctly 

 referred to this species. 



Melania australis, Lea. 



Bef.—Proc. Zool. Soc, 1850, p. 185 ; Beeve, Icon. Con., t. 12, 

 f. 82. 



Hah.—'RiYev Victoria (N. . Aust. Exped., 1855) ; Port 

 Essington (Brit. Mus.). 



Melania carbonata, Reeve. 

 Bef.—Icon. Con., fig. 88, 1859. 

 Hah.— Foxt Essington (Brit. Mus.). 



Melania venustula, Brot. 

 Bef.—Con. Cab. ed. 2, p. 331, t. 34, fig. 5, 1874 ; Smith, Proc. 

 Lin. Soc, 1882, t. 5, figs. 9-10, p. 260. 



Hah. — Eiver Victoria (N. Aust. Exped.). 



Melania onca, A. Adams and Angas, 

 Bef.—Proc. Zool. Soc, 1863, p. 415 ; id, Brot, op. cit., 



p. 330, t. 34, f . 7. 



Hah. — Mary Eiver, Arnheim Land (Stuart Exped.) ; Eiver 



Adelaide (E. T.). 



