Fossil Fauna, Table Cape Beds, Tasuiania. 117 



unknown, all the examples at present under examination being 

 imperfect in tliis respect. Spire-whorls about four in number, 

 rapidly inci'easing in size to the large and broad body-whorl, 

 almost perfectly flat at first near the posterior suture, then flatly 

 convex to the well-developed and characteristic keel, the latter 

 being situated so close to the anterior suture that owing to its 

 strong development and ornamentation the suture is completely 

 hidden. Body-whoi4 keeled at the periphery, base almost flat, 

 being slightly convexly rounded from the keel to the umbilicus. 

 Aperture oval, nacreous internally, peristome almost continuous, 

 but falls a little short at the posterior of the inner lip. Outer lip 

 smooth intei-nally, thin at the edge, and slightly crenulated at 

 the ends of the coarse spiral threads ; inner lip strongly reflected 

 over the umbilicus. Umbilicus nearly circular, wide, and very 

 deep, penetrating up the spire as far almost as the embryonic 

 whorls, rather strongly angled by two revolving keels. The 

 surface ornament consists of coarse and fine granulose or squamose 

 spiral threads and a strong peripheral keel. The keel carries a 

 number of stout, erect, forwardly projecting and very prominent 

 scales, which are ornamented with fine threads in uniformity with 

 tliose of the same degree of strength on the remainder of the shell. 

 In a large specimen these peripheral scales number about twelve 

 on the body-whorl, in smaller examples they are slightly less in 

 number. Basal ornament consists of about six or seven coarse 

 spiral threads, which bear numerous and comparatively coarse 

 forwardly projecting scales, commonly, however, worn down to a 

 more or less granulose appearance ; intercalated between these 

 are finer threads, which are similarly though not so coarsely 

 ornamented. The spiral ornament is crossed by close, fine, and 

 slightly raised lamellae parallel to the lines of growth. Umbilicus 

 partly margined by a revolving area, which only shows the 

 lamelhe of growth, and partly by an area bearing spirally 

 revolving threads similar to those above described. 



Dimensio/is. — Height about 30 mm. ; breadth to extremities of 

 peripheral scales, 66 to 69 mm. ; height of aperture, about 

 19 mm.; breadth of aperture, 27 mm.; width of umbilicus, 

 11 mm. Much smaller specimens occur having a basal diameter 

 of from 32 mm. to 40 mm. 



