228 ASTRALIUM. 



A. iiELioTROPiUM Martyn, 1784. PI. 56, fig. 87. 



Shell large, depressed-conic, below widely uaibilicate and concave, 

 spire dome-shaped, of 5 convex whorls ; suture rendered zigzag by 

 the prominent compressed triav.gular recurved vaulted spines which 

 arm the acutely carinated periphery ; whorls above and below with 

 numerous spiral series of granules ; umbilicus wide, deep, coarsely 

 obliquely striate within ; aperture transversely oval, oblique, pearly 

 Avithin, peristome continuous ; columella slightly dilated, impinging 

 upon the umbilicus ; color brownish or ])urplish above, light below. 



Alt. 50-60, diam. 100-120 mill. 



Neiv Zealand ; Hauraki Gulf, Foveaux Sts., Cook's Sts., Bay of 

 Tasmania. 



Operculum (pi. 59, figs. 5, 6) oval, with cxcentric nucleus ; outside 

 smooth, obsoletely unicostate. 



The synonyms are. Trochus solarium imjjeralis etc. Chemnitz, T. 

 imperialis Gmel., and of most authors, Imperator aureolatus Mont- 

 fort, and Guildfordia lieliopliorus Gray. 



This large handsome species was brought to Europe for the first 

 time by the famous Captain Cook. 



Subgenus Guildfordia Gray, 1850. 



Shell wheel-shaped, imperforate ; hnv-conic and graiiulose above, 

 convex below, periphery armed with long slender radiating spines, 

 "which are concealed at the sutures ; operculum flat, with a subol)so- 

 lete arcuate rib outside. 



Ja])onic Province. 



A. TRiuMPHA>'s Phil, 1841. PI. 58, figs. 67, 68. 



Shell low-conic, imperforate, metallic brownish-purple above, 

 nearly white below ; whorls 6, slightl}^ convex above ; body-whorl 

 armed around the carinate i^eriphery with long slender closed tubu- 

 lar radiating spines, about eight in number on the body-wdiorl, 

 and Avhich are reabsorbed as the growth advances leaving only short 

 stumps to festoon the sutures ; upper surface with close revolving 

 series — generally eight to ten on the last whorl — of minute laterally 

 compressed granules; base slightly convex, usually w'ith a marginal 

 row of granules, and several rows surrounding the central callus ; 

 aperture transversely ovate, angulate and channelled at peri})heral 

 carina, iridescent within ; peristome sinuous above ; umbilical re- 



