COOKE : ON AUSTRALIAN LIMJ<!MM. 243 



Limncea and not of a Fhysa, a. surface comparatively coarse and 

 rough, with none of the polish and lustre which is seen on the 

 shell of a Physa, and which is produced by the constant move- 

 ment of the expanded mantle lobes which cover its outer surface. 

 Add to this the exceeding deep suture, the gaping umbilicus, 

 and the very strongly reflected columella. Smith, on " Fhysa 

 Newcomhi" remarks (ut suj>ra), " the great development of the 

 labium is very unusual in this genus." 



Sinistral species of Li?nncea exist, according to Tryon, 

 "Structural and Systematic Conchology," vol. iii., p. loi, in New 

 Zealand and the Sandwich Islands. He makes no mention of 

 any in Australia. 



I will now describe the shell which appears to me a new 

 species of Limjicea. 



Limnaea physopsis n. sp., plate ii., figures i — 4. 



Shell sinistral, very ventricose, solid, opaque, scarcely 

 lustrous, horn colour, with bands of deeper colouring at the 

 lines of growth, strongly striated lengthwise, with faint indica- 

 tions of keels here and there on the last whorl; Epidermis thick; 

 Whorls 4, the last occupying nearly all the shell ; Spire blunt 

 and flattened; Suture very deep; Mouth very large, rotundate- 

 oval; Outer Lip rather strong, not reflected; Inner Lip strongly 

 reflected on the columella; Umbilicus large and deep; length 

 •75 inch, breadth 75 inch. 



Habitat, Paroo Creek, River Darling, Australia. 



Type, in the British Museum. 



For purposes of comparison, I add (pi. ii., figs. 5, 6) drawings 

 from photographs of the radula of Lwuicea physopsis x 72, and 

 of a typical Fhysa (acuta. Lam.) x 210. 



