On Some New Marine Mollusca. 83 



characteristics of this shell. In the family of Unionidae the 

 genus Spathdj of Lea, is the only one that comes at all s near 

 it. The latter includes rounded thick shells covered with a 

 persistent reddish-brown periostraca and a smooth arcuate 

 hinge margin. Three species of Spatha are noted by Messrs. 

 Adams, which are from Senegal and the River Nile. The 

 species I now describe is not nacreous, and the valves are 

 covered with concentric lamella?. 



A. sordida, PL, Jigs. 10, 11, n.s. T. sub-orbicidari, 

 tenui, tumida, sordida, periostraca luteo-olivacea, sordida, 

 valde erosa, postice parurw cmgulata ; lamellis concentricis 

 incequalibus conspicvAs ; intus alba, costis obsoletis, radi- 

 antibus mwmta periostraca, late marginata; cardine 

 dente inconspicuo arcuato, liga/mento crasso. Diam. 30 ad 

 5, Mil. Alt., 2-valv., conjunctis 15 ad 30. 



Shell sub -orbicular, thin tumid, sordid, periostraca yellow- 

 ish olive, much eroded at the umbones, slightly angular pos- 

 teriorly, with unequal concentric lamella?, white inside, with 

 radiating obsolete ribs broadly margined at the edge with 

 periostraca, ligament thick, with an inconspicuous arcuate 

 smooth tooth. 



This shell is found in the fresh-water or brackish-water 

 swamps about Bowen, at Port Denison. It is largely eaten 

 by the natives, who have left it in heaps in the sand-hills at 

 their former camps close to the sea-shore. 



EXPLANATION OF PLATE. 



Fig. 1. Purpura Baileyana — Front view. 2. Back view, natural size. 



Fig. 3. G-ibbula tesserula — Shell, much enlarged. 4. Base. 5. Spire. 



Fig. 6. Fossarina funiculata — Spire. 7. Base; both magnified 8 diam. 



Fig, 8. Cliiton inornatus — Natural size. 9. Single valve, enlarged to 

 show the absence of ribs and the dotted ornamentation. 



Fig. 10. Austriella sordida — Upper surface, natural size. 11. Interior 

 of valve. 



G 2 



