Fossil Fauna, Table Cape Beds, Tasmania. 105 



present examination goes. Embryonic whorls succeeded by eight 

 spire-whorls, which are slightly more convex posteriorly and be- 

 come flatter anteriorly, with a moderately well-defined suture, 

 but no well-marked subsutural groove or sulcus ; anterior slope 

 of body-whorl somewhat abrupt. Aperture narrow elongate- 

 oval ; outer lip thin and simple, somewhat thickened at the 

 suture. Columella simple and slightly arched. Canal very short, 

 comparatively wide, and a little upturned at the anterior end. 

 At the base or anterior end of the shell a prominent ridge runs 

 round from the anterior outer end of the canal just up to the 

 columella. 



Surface ornamented with very slender acute costte, with much 

 wider and shallow interspaces between. The interspaces become 

 wider anteriorly, being about twice or slightly more than twice 

 the width of the costte on the body and penultimate whorls. 

 The costie are practically straight, very slightly elevated above 

 the general surface of the shell, number twelve to a whorl and 

 are smooth. Below the posterior suture of each whorl there is a 

 tendency towards the development of a subsutural depression, 

 which, however, has only affected the costa^, and the latter on 

 this account appear faintly tuberculate in this region. The 

 surface also shows fine lines of growth and striations pai'allel to 

 the costae, but the only spiral ornament consists of exceedingly 

 faint and microscopic striations, which are not visible to the 

 unaided eye. 



Dimensions. — Length of eight whorls with embryo, 13 mm. ; 

 breadth of body-whorl, 3'5 mm. ; length of aperture and canal, 

 3 mm. 



Locality. — Eocene beds of Table Cape, Tasmania. 



Observations. — This form seems at present sufficiently distinct 

 from our previously described species of the genus to necessitate 

 its record as new. It however shows some affinity with T. 

 additoides, T. Woods, from beds of the same horizon, and with 

 T. leptospira, Tate, from the eocene beds of Muddy Creek. From 

 T. additoides it may be distinguished by its more slender and 

 rapidly tapering spire, flatter whorls, much less numerous costse 

 (or plicte as they are referred to in the description of tliat species), 

 and the absence of the distinct subsutural band ; and from T. 

 leptospira it is also I believe distinct, but owing to the exceed- 



