168 



Dimensions. — Length, 30; breadth, 21; length of aperture, 25. 



Locality. — Bairnsdale, Gippsland ( W. H. Gregson I). 



This fossil shell has the shape of S. ahbreviata, Lamarck, recent 

 on the west coast of Tropical America, from which it differs by 

 the three subdistant rows of tubercles and its smooth inner lip. 



5. Semicassis radiata, spQc nov. Plate viii., fig. 3. 



Shell globosely ovate, spire of moderate length, acuminate, 

 ending in a small pullus of one and a half smooth convex whorls. 



Whorls four, excluding pullus, convex, but interrupted by a 

 broadish concave depression in front of the marginal rib at the 

 anterior suture. 



Posterior whorls ornamented by straight, rather crowded, 

 slender cost?e, which terminate behind at the ante-sutural de- 

 pression. 



Last whorl ventricose, contracted at the base, and concavely 

 depressed in front of the suture, from which it is separated by a 

 nodosely-crenulated band ; ante-sutural zone with three or four 

 spiral threads. Median portion ornamented with angular, slightly 

 elevated, moderately curved costse (about 24); at first slender 

 and crowded, but become stronger and more widely separated 

 with the revolution of the whorl, and are absent in the last- 

 fourth. The costfB are interrupted on the shoulder by three in- 

 conspicuous angulations ; otherwise the surface anterior to the 

 sutural zone is without spiral ornament, except some obscure lines 

 at the base. 



Aperture ovate ; outer lip thickened, margin plain, slightly 

 ascending on the penultimate whorl. Columella convex, its sur- 

 face without granulations, with fine slender revolving plaits ; a 

 small tubercle at the posterior angle of the aperture. 



Dimensions. — Length, 23; breadth, 15 ; length of aperture, 18. 



Locality. — In a well sinking, Murray Desert. 



This species approaches the nodulate variety of aS'. torquata^ 

 Reeve, recent in temperate waters of Australia ; but it differs by 

 its finer ornamentation, more developed costae, shorter spire, 

 more tumid body whorl, by the presence of slender threads on the 

 ante-sutural band, and by its smooth outer lip. 



Genus Cassidaria. 

 synopsis of species. 



Whorls sharply gradated, unequally and distantly lirate ; keels 

 on body whorl with crenate tubercles. 1. C. gradata. 



Whorls angular, regularly lirate ; keels on body whorl with 

 transverse tubercles ; less ventricose. 2. C. Wilsoni. 



