496 STUDIES ON AUSTRALIAN MOLLUSCA, 



name I had proposed to bestow, and leave the specific status to 

 be decided by one commanding a larger series. 



Shell small, much higher than long and very shallow. Colour 

 reddish-brown, passing into yellow at the apex, irregularly 

 splashed with dark brown and opaque white. Anterior auricles 

 largely, posterior moderately developed, anterior with six, posterior 

 with four strong radiating, nodulose ribs. The radial ribs of the 

 valve number about sixteen; they increase either by interpolation 

 or by an even splitting of the primary ribs; their interstitial 

 grooves are broad and deep. This sculpture scallops the margin 

 and prints the -interior. The whole external surface is covered 

 by minute, frail, imbricating scales; arched in the grooves and 

 flat on the ribs (fig. 12). The ctenolium has five well developed 

 and one rudimentary tooth, crowded together. Hinge plate 

 broad. One faint cardinal rib on either side. Resilium small. 

 Chondrophore well within the margin. Height 24, length 20-5, 

 breadth of conjoined valves 7 mm. 



Hob. — Off Green Point, Port Jackson; two specimens dredged 

 by Mr. J. Brazier, 10th July, 1886, in 8 fathoms, on a bottom of 

 stones and sand, with broken valves of Trigonia. 



T y p e to be presented to the Australian Museum. 



The delicate microscopic sculpture of this species should serve 

 to distinguish it readily; at first sight one might think the valves 

 were encrusted with Polyzoa. 



Arcoperna recens, Tate. 



Tate, Proc. Malacological Soc. ii 1897, pp. 181, 182, three 

 figures in the text. 



Prof. Tate has, in adding a species and a genus to the Aus- 

 tralian fauna, also made known as living a genus, Arcoperna, 

 previously only recorded as an Eocene fossil. His material was 

 taken at Port Esperance, Tasmania. I am now enabled to add 

 this most interesting survivor of bygone ages to the list of New 

 South Wales mollusca through the kindness of Mr. J. Brazier, 

 who has shown me a specimen dredged by himself in 8 fathoms 



