172 



Zenatiopsis angustata, Tate. 

 Reference— Trans. Koy. Soc, S. Aust., 1879, p. 129, t. 5, 



Externally like the living Zenatia acinaces, Quoy and Gai- 

 mard, but is narrower, more attenuated posteriorly, and the 

 .anterior side is longer and not so abruptly arched ; internally 

 it differs by the presence of a thick rib descending vertically 

 from the umbo. 



Localities. — Gastropod-bed of the River Murray Cliffs near 

 Morgan; upper and lower beds at Muddy Creek ; Table Cape 

 (Hobart Mus. /) 



FAMILY PAPHIID.E. 

 Anapa variabilis, spec. nov. Plate xvii., figs. 5a — 5b. 



Ovately-trigonal, rather thin, inequilateral ; umbones in- 

 -flated, antemedian ; posterior side the longer, bluntly rounded at 

 Hie extremity ; the anterior end is rounded, and the front- 

 dorsal slope slightly incurved. The surface is ornamented 

 with moderately line growth ridges and striae. 



Dimensions. — Antero-posterior diameter, 17'5 ; umbo-ventral 

 diameter, 13'5 ; sectional diameter of united valves, 11 milli- 

 metres. 



Locality. — Common in the oyster banks of Blanche Point 

 Cliff, Aldinga Bay. 



The figured example fairly represents the mean of extremes 

 of form assumed by this species, which is closely related to 

 A. cuneata and A. triquetral from which it differs by its greater 

 gibbosity, rounded posterior extremity, and the convex not 

 flattened posterior slope. Some very young examples are 

 triquetrous, and with difficulty separable from A. triquetra at 

 the same stage of growth. 



FAMILY ANATINID.E. 

 Thracia perscabrosa, spec. nov. Plate xv., fig. 5. 

 Right valve moderately convex, ovately-oblong, narrowed in 

 front and broadly truncated behind ; umbones post-median ; 

 posterior area concavely depressed, separated from the rest of 

 the valve by a rounded carination extending from the umbo to 

 the post-ventral angle. The post-dorsal margin is nearly 

 straight, nearly parallel with the ventral margin ; the front 

 dorsal margin is somewhat ecurved and oblique. The anterior 

 end is rather wedge-shaped, and rounded at the extremity; the 

 posterior end is abruptly truncated, forming a rounded angle 

 with the ventral margin, and an obtuse angle (about 105 deg.) 

 with the dorsal margin ; the ventral margin is very little 

 curved, ascending in front. 



