80 Proceedings of the Royal Society of J^ictoria. 



costated whorls, eiidins; in ;i full ventricose body-whorl with ;i 

 comparatively large aperture, and with a very short twisted 

 canal.' 



Apical angle about fifty to tifty-tive degrees. Apex consists of 

 about two smooth, well-defined convex embryonic whorls, with a 

 centrally immersed tip. Emljryonic whorls succeeded by five 

 gradually increasing, markedly convex whorls, with a well-defined 

 and somewhat impressed suture, occasional specimens being more 

 constricted at the suture than the usual type. The greatest con- 

 vexity about the middle of each whorl, with a tendency to 

 shouldering at about the posterior third, as a consequence of the 

 slope of the posterior third of each whorl being somewhat more 

 sudden and flatter than the more regularly convexly rounded 

 anterior two-thirds. Spire-whorls terminate in a broad ventricose 

 body-whorl, with a rather large oval aperture. 



Outer lip thin and sharp at the outer edge, slightly thicker 

 internally, and bearing about twenty to twenty-two close, narrow, 

 and short ridges in its full length from its junction with the 

 anterior canal to the posterior suture. Inner lip very thin and 

 concavely arched to the columella, the latter being rather strongly 

 twisted. Canal very short, strongly bent to the left, finally some- 

 what reverted, and at the same time upwardly raised. 



Surface ornamented with transverse cost^e crossed by relatively 

 coarse and tine spiral threads. The earlier half of the first spire- 

 whorl is finely and very closely costate, bearing about five or six 

 fine cost*. Subsequently the costie become relatively broader 

 and much wider apart. The ordinary costje are narrow, with 

 much broader interspaces between them, fade out before reaching 

 the posterior suture, and usually developed right up to the 

 anterior suture. In number they run from al)out nine to eleven 

 to a whorl, and in some specimens show a tendency to become 

 obsolete on the body-whorl. The costte and interspaces are 

 traversed by lines of growth and fine close strite parallel to them. 

 The transverse strite ai'e occasionally more noticeable on the 

 posterior whorls, whei'e they are sometimes sufficiently strong to 

 give rise to a fine cancellated ornament by being crossed by the 

 spiral threads. The whole of this transverse ornament is crossed 

 by spiral threads, from five to seven of which are stouter than the 

 remainder ; and of these, three or four on the anterior slope of 



