146 



Trigonia Hovs/^itti, McCoy. 



Reference. — Palaeontology of Victoria, Dec. III., pi. xxvii., 

 figs. 1— 2c, 1876. 



Locality. — Sandy marl at Jemmy's Point, near the entrance 

 of the Gippsland Lakes, collected by Mr. A. Howitt, after 

 whom it is named. 



FAMILY CEASSATELLID^. 

 GrENUS CeASSATELLA. 

 SYNOPSIS OF SPECIES. 



A. Valves with plain margins. 



Elongate ovate-trigonal. C ohlonga. 



Subquadrate ; fine concentric folds. C astartiformis. 

 Subquadrate ; tumnlous concentric ridges. G. corrugata. 

 Subtriangular, anterior side very short, fine concentric 

 folds. C. ahbremata. 



B. Values with crenated margins in the adult. 



Ovate-oblong ; concentrically folded. C. Dennanti. 



Ovate-trigonal ; nearly smooth. C ajylirodina. 



Crassatella oblonga, Tenison- Woods. 



Reference, — Proc. Eoy. Soc, Tasm., for 1875, t. ii,, fig. 11, 

 p. 25. 



Localities. — Tasmania : Table Cape ! (JR. M. Johnston) . Vic- 

 toria : Muddy Creek. South Australia : Oyster beds, North- 

 West Bend, E-iver Murray. 



Very distinct from any existing species ; is somewhat like 

 C. attenuata, Hutton, of the Older Tertiary, New Zealand. 



Crassatella Dennanti, spec. nov. Plate xi., fig. 2. 



Shell ovate-oblong, moderately convex, inequilateral ; um- 

 bones anterior ; rounded in front, expanded, flattened, and 

 obliquely truncated behind. Surface closely and irregularly 

 concentrically folded, folds narrow, about as wide as the fur- 

 rows, acutely rounded, minutely and regularly radially striated ; 

 the broad posterior flattened area is faintly marked by a median 

 ridge, the lamellae of growth in the form of thin imbricating 

 plates. Lunule impressed lanceolate. Hinge area narrow ; 

 left valve with two cardinal teeth in front of the cartilage pit, 

 and one lamellar tooth posteriorly ; right valve with three 

 cardinal teeth in front of the pit, the middle one very thick 

 and crenulated on the side, the outer one small and marginal. 

 Inner margin of valves denticulated. 



Dimensions. — Length, 57 ; width, 37 ; thickness through both 

 valves, 32 millimetres. 



Locality/. — Not rare Muddy Creek, Hamilton (J. Dennant). 



