310 Chapman and Gahrid : 



Fam. CARDITIDAE. 

 Genus CARDITA. Brubudiere. 

 Cardita calva, Tate. (Plate XXVIL, Fig. 18). 

 Cardita calva, Tate, 1887. Trans. Roy. Soc. S. Austr., vol. 

 ix. p. 189, pi. XX. fig. 14. 

 This species is not found below the Kalimnan series. As Tate 

 remarks, it is nearest allied to C. compacfa, but is distinguished 

 by the smooth umbones. and it also slightly differs in shape. 



C. calva is very abundant in the younger beds in the Mallee 

 bores, and shows a surprising amount of variability in the surface 

 ornament. One of the extreme forms is now figured, in which the 

 cancellate ornament, produced by the crossing of the concentrics 

 by the radials is confined to a narrow strip on the posterior 

 margin. 



This species is found graduating into Cardita dilecta, var. 

 excelsior, Verco, ^ a living Australian form; some specimens of the 

 fossils matching it so closely as to be inseparable. 



Distribution.— Bore 1, 215-244 feet. Bore 3, 201-220 feet; 226 

 feet. Bore 5, 163-175 feet. Bore 6, 114-150 feet; 158-161 feet. Bore 

 8, 165-180 feet; 210-219 feet. Bore 9. 254-256 feet; 263-273 feet;. 

 315-325 feet. Bore 10, 230-254 feet. Bore 11, 197-199 feet. 



Cardita spinulosa, Tate. 

 Cardita spinulosa, Tate. 1886, Trans. Roy. Soc. S. Aust.,. 

 vol. viii. p. 153, pi. ii. fig. 3. 



This species is evidently very closely related to Carditella tor- 

 resi, E. A. Smith, 2 which, by the way, according to that author,, 

 is not typical of the genus Carditella, in its ligamental characters.^* 

 The only difference between the recent species quoted and our 

 fossil specimens appear to be in the lighter hinge area of the living 

 form. 



Cardita spinulosa, Tate, is represented in the bore by small 

 specimens of the normal subrotund shape of the neanic examples, 

 as distinguished from the ventrally truncated forms in the gerontic 

 stage. 



Distribution.— Bore 3, 226 feet. Bore 6, 158-161 feet. Bore 10, 

 310-320 feet. 



1. Venericardia dilecta, K. A. Smith, v.ir. excflmor, Verco, Trans. Roy. Soc. S. Austr., vol. xxxli.,. 

 1908, p. 348, pi. xiv., fit,'. 9. Cardita calva, Tate. Gatliff and Gabriel, Proc. Roy. Soo. Victoria,, 

 vol. XXV. (n.H.), pt. i., 1912, p. 173. 



2. Rep. (Jhall. Zool., vol. xiii., Lamellibraiifhiata, p. 'JIT, pi. xv., fi(;8. 8. 8a. 



3. Loc. Bupra oit., p. 218. 



