28 Proceedings of the Royal Society of Victoria. 



sharper posterior termination, a broader and more marked 

 bevelled margin, and lacks the regular concentric threads which 

 mark the whole of the external svirface, forming a characteristic 

 of the abovementioned species. It is also closely related to a 

 fairly abundant species from the Lower Spring Creek beds, near 

 Geelong, but it seems advisable to make distinction between the 

 two, and I therefore include the following particulars on the 

 Spring Creek shell. 



Leda fontinalis, sp. nov. (PI. III., Figs. 3, 3a.) 



Description. — This species is very similar to the foregoing, and 

 many points in that description apply well to the prcisent form, 

 but the anterior of the shell is not so regularly convexly rounded, 

 having a tendency to be somewhat angled on account of the 

 sudden junction with a very straight ventral margin, and the 

 posterior end of the shell is more acute for the same reason. 

 The valves are deep, so that pairs in conjunction give a very 

 tumid shell for the size ; on account of the greater inflation the 

 keeling is more marked and there is a broader flattened area 

 behind the umbones. The hinge teeth are smaller, closer, and 

 slightly more numerous, there being about 15. 



Umbones smooth, and earlier portion of the shell with no 

 specially distinct marking, then fairly regular incised concentric 

 grooves, with broad flat spaces between become prominent, with 

 occasional growth folds at irregular distances. 



Dimensions. — Type specimen, antero-posterior diameter, 

 6-5 mm.; umbo-ventral diameter, -1 mm.; thickness through both 

 valves, 4 mm.; another specimen of the same size shows slightly 

 less inflation, being a little under the 4 mm. in thickness ; other 

 examples range in their diameters, 6 mm. by 3-5 mm., 5-J- mm. 

 by 3-5 mm., and 4-5 m.m. by 3 mm. 



Locality. — Eocene, lower beds of the Spring Creek or Bird 

 Rock Blufi^ Section, near Geelong. 



Observations. — This is probably the species referred to under 

 the manuscript name of L. embolos, by Professor Tate. 



Carditella regu lapis, sp. nov. (PI. II., Fig. 5). 

 Description. — Shell small, rotund, and convex, with prominent 

 incurved anteriorly directed umbo, and a small but well-defined 



