214 



proportional width is ,-^^3, height, y^y% ; but dwarfed examples of 

 from 10 to 15 mm. are more common. 



LocaHties. — This is one of the commonest and most widely 

 diffused species of the Australian Eocene-beds. South Austra- 

 lia. — River Murray Cliffs ; Turritella-clays, Aldinga-cliffs ; bore 

 at Adelaide. Victoria.— Schnapper Point !, Muddy Creek ! and 

 Corio Bay ! (McCoy) : Spring Creek ! Tasmania. — Table Cape ! ; 

 and Turritella-limestones, Flinders' Island (Johnston). 



2. Trivia erugata, -sj^ec. nor. 



Sliell thin, narrowly oblong, spire concealed. The back is 

 broadest and highest near the j^osterior end, is depressedly convex 

 in a longitudinal direction, abruptly sloping to the posterior end, 

 but more gently to the front ; the right side is rather steep, 

 medially slightly depressed, the left side is more convex. In 

 young shells the median constriction is very pronounced, and the 

 spire is prominently exsert. 



The aperture is narrow ; the outer lip narrowly thickened and 

 indistinctly margined, it is slightly incurved medially, rounded at 

 the extremities, and ornamented with about 25 teeth. 



The cross-ribs are evanescent at about half the length of the 

 sides, being thus interrupted by a large oval smooth dorsal area. 



Dimensions. — Length, 5*5 ; greatest width, 3 ; and height, 2*5. 



Locality.— 'LowQVYnost horizon of the Muddy Creek-section. 



T. erugata differs from known, recent and fossil, species by the 

 combination of an oblong shape with a large smooth dorsal area. 



3. Trivia pompholugota, spec. nor. 



Shell globose, smooth and shining, abruptly descending to the 

 excessively short anterior canal and to the slightly-projecting 

 s^Dire. 



Aperture moderately wide, rounded behind. Outer lip slightly 

 pi'ojecting behind, narrowly thickened and inflected, minutely 

 wavy-wrinkled, margined externally, provided with sixteen stout 

 elevated ridges ; inner lip with a keel-like margin, which is tuber- 

 culate-dentate (eight tubercles in the anterior-half and sixteen in 

 two rows in the posterior-half) ; the columella-plate is high, flatly- 

 concave, smooth, and reaches to the front. 

 -Dimensions. — Length, 7"5 ; width, 5 '5; height, 5. 



Locality. — Adelaide-bore. 



The apertural characters, which, however, indicate a somewhat 

 adolescent shell, are those rather of Trivia than Cyprc^a. 



Genus Erato. 

 The affinities of this genus are considered by some concholo- 

 gists to be with MargineUa, but I revert to its location in the 

 Family Cypr^eida^. 



