94 Proceedings of the Royal Society of Victoria. 



flattened, and being devoid of the strong corrugations charac- 

 teristic of the remainder of the shell. 



Anterior margin convexly rounded, ventral margin slightly 

 convex to almost straight, posterior truncation strongly marked, 

 and post-dorsal margin usually very straight, sometimes slightly 

 concave. Umbos strong and very acute and well incurved. 

 Lunule long, narrow, and somewhat impressed. Surface closely 

 set with very fine concentric lines of growth, most distinct on 

 the posterior slope and towards the anterior of the shell, the 

 median portion being occupied by strong concentric corrugations. 

 Umbo very closely and regularly corrugate, in 3 mm. from the 

 beak there are 14 corrugations, the corrugations here extending 

 also on to the posterior slope; from the umbonal region towards 

 the ventral margin the corrugations become broader, with shallow 

 interspaces, flattening and thinning out towards both the anterior 

 and posterior. Hinge teeth large and strong for the size of the 

 shell, with a large deep cartilage or resilium pit, inner margin of 

 the valves smooth. 



Dimensions. — Type, antero-posterior diameter, 56 mm.; umbo- 

 ventral diameter, 36 mm.; an example of the paired valves 

 measuring 55 by 33 gave a thickness through both valves of 25 

 mm. Other examples range 60 by 36, 58 by 36, 59 by 35, 52 by 

 32, 47 by 30, and 39 by 25. 



Localities. — Lower and Middle beds of the Spring Creek 

 series, or Bird Rock Bluff, near Geelong ; Lower beds at Maude, 

 Moorabool Valley. Jan Jukian, — Eocene. 



Observations. — -This is a well-marked and distinctive species 

 which shows some relationship to C. dennanti, Tate. Its char- 

 acters are usually fairly constant, but some specimens are so 

 straight along the ventral margin as to intensify the posterior 

 angulation to a marked degree, and in some again the concentric 

 corrugations are more persistent towards and up to the anterior 

 end. 



Crassatellites kingicoloides, sp. nov. (PL XIII., 



Figs. 1, 2, 3). 



Description. — Shell large, strong and solid, broadly ovate, with 

 prominent and large umbos, and rather a strongly marked and 



