242 ASTRALIUM. 



T. brevispinosus Sowb., T. inermis Luni. and some authors, are syn- 

 onymous. Differs from A. olivaceum in the white umbilical callus; 

 from A. unguis in the sculpture of the base. 



A. UNGUIS Wood. PL 53, ftgs. 34-36. 



Shell conic, solid, imperforate, brown or gray ; spire conic, acute ; 

 whorls 6, above very obliquely striate and flattened, longitudinally 

 irregularly plicate, sharply carinated at the periphery and produced 

 into radiating compressed truncated digitations ; base flat or concave, 

 concentrically regularly and finely lirate, lira? about seven in number, 

 radiately densely, finely lamellose-striate ; aperture very oblique* 

 silvery within, angular at periphery, lower margin nearly straight; 

 columella oblique slightly concave, excavated at position of umbili- 

 cus, with a spiral white rib ; parietal callus covering over half the 

 base of the shell. Alt. 40. diam. 50 mill. 



Panama to Mazatlan. 



Operculum (pi. 59, fig. 17) white outside, excavated on each side 

 of a strong granulose curved central rib. the terminations connected 

 by a shorter ridge curved in the opposite direction. 



T. amictus Val. and T. multipes Phil, are synonymous. T. digita- 

 tus Desh. is a variety with strong longitudinal folds (fig. 34. ) 



Subgenus COOKIA Lesson, 1832. 



Shell large conical, imperforate; periphery rounded ; base con- 

 cave ; umbilical tract concave, smooth ; operculum ovate, narrowed 

 toward the distal extremity, nucleus subterminal, outside with two 

 convex smooth ribs. 



-1 ustralo-Zealandic Province. 



A. SULCATUM Martyn, 1784. PL 64, fig. 55. 



Shell large, conic, imperforate, rather thin ; spire more or less 

 elevated ; sutures deeply impressed ; whorls 7, well rounded, with 

 close lamellose incremental stria?, and corrugated by obliquely des- 

 cending subtuberculose folds ; periphery rounded, base flattened, 

 bearing concentric .densely squamose lira?, deeply concave in the cen- 

 ter, and indented in the place of the umbilicus ; aperture transverse- 

 ly oval, very oblique, pearly and somewhat corrugated within ; col- 

 umella arcuate, thin ; umbilical region and part of base covered with 

 a thin callus. Alt. 65-80, diam. 90 mill. 



New Zealand; Chatham Is. 



Operculum (pi. 59, fig. 26) brownish or white outside. 



