658 DESCRIPTIONS OF TWO NEW SPECIES OF AUSTRALIAN MOLLUSCA, 

 PAPERS READ. 



DESCRIPTIONS OF TWO NEW SPECIES OF 

 AUSTRALIAN MOLLUSCA. 



By James C. Cox, M.D., F.L.S. 



Ancylus Smithi, sp.nov. 

 (PL XIX., figs. 1-3). 



Shell ovate, broadest in front, pale horny yellowish-green 

 colour, translucent, limpet-shaped; striated concentrically from 

 apex to circumference with curved lines of growth, the apex 

 being the centre of the rays ; striated longitudinally with strise 

 radiating from the apex in rather coarse ridges, which are for 

 the most part rather widely separated, but are irregular in dis. 

 tance from each other, and if anything interrupted in their 

 direct course, and are not quite straight. The lines are un- 

 doubtedly slightly waved. These can only be seen with a 

 moderately high power. These strise can be seen through the 

 shell when the animal is removed. 



The apex is bluntly rounded, inclined to the right, and the 

 shell declines from it less abruptly in front than it does behind 

 and at the sides, where it gradually tapers off, and is situated 3^ 

 millimetres from the anterior margin. The shell, looked at from 

 the inside, shows the muscular impression, which is rather large 

 and granular. 



When the animal is in the shell a brownish colour is seen 

 opposite the muscular impression. 



Dimensions of full-grown shell — length 5 ; breadth (at anterior 

 end) 3, (at posterior end) 2 ; height 1 J millimetres. 



The living specimens of this Ancylus or River Limpet now 

 described, and which were exhibited at the last meeting of the 

 Society, were obtained by me from the Port Hacking River, 

 National Park, about twenty miles south of Sydney, quite unex- 

 pectedly, and they have bred and multiplied themselves to a very 

 arge number. 



