164 



FAMILY CASSIDID/E. 



Genus Cassis. 

 synopsis of species. 

 Shell oblong-ovate, 12 tubercles in each row in front of the- 

 last varix ; posterior slope of last whorl precipitous ; suture^ 

 margined with granulose-crenulations. 1. C. exigua^ 



Shell ovate, 9 tubercles in each row, posterior slope concavely 

 sloping upw^ards, distantly wrinkled at the suture. 



2. G. textiUs.. 



SPECIES EXCLUDED. 



C. sufflata, Tenison Woods, is tranferred to Semicassis. 



1. Gsssis exigua, Tenison Woods. Plate vii., fig. 13, 



Reference. — Proc. Lin. Soc, N.S. Wales, vol, iv., p. 17, tab. 2^. 

 fig. 7 (1879). 



Shell stout, oblong-ovate, ventricose, with a A'ery short conic 

 spire, ending in a small pullus of one and a half smooth swollen 

 turns, with the tip reverted and immersed. Whorls five, exclud- 

 ing pullus, variced at successive intervals of about two-thirds of 

 a whorl, the first whorl transversely corrugate and spirally striate; 

 sutures granulosely marginate. 



Last whorl with a very high back, somewhat precipitous over 

 the suture ; bearing on the angle a row of 12 compressed sharp- 

 2>ointed tubercles, and on the medial portion two other rows equi- 

 distantly placed, but of smaller size, a fourth inconspicuous row 

 is developed on the adult shell. Base somewhat cancellated. 



Aperture narrow, sinuously curved at each end ; outer lijD flat- 

 tened, inflected, and slightly reflected, plicately dentate. Inner 

 lip widely spreading, projecting behind as a thin plate, and ter- 

 minated by the varix, over w^hich it projects. Columella strongly 

 dentately wrinkled throughout, as well as the anterior portion of 

 the callous-covering. 



Dimensions. — Length, 40 ; breadth of last whorl, .30 ; height, 

 27 ; length of aperture, 37 ; but attains to a length of 52. 



Locality. — Lower beds at Muddy Creek. 



It is hardly possible to recognise in the shell, vrhich I have 

 figured, an adult example of the very juvenile specimen which is 

 the author's type of the species ; but I have had that under 

 examination, and have been able readily to trace it through a 

 long series of graduating specimens. 



In its adult state the species closely resembles C. fimhriata, 

 recent in Southern Australia, from which it difiers particularly 

 by the spiral sculpture. 



