150 HELCIONISCUS. 



The name Cellana has priority over Helcioniscus but it has not 

 been adequately defined. 



H. PROFUNDUS Deshayes. PI. 65, figs. 94, 95, 96. 



Shell small, elevated-conical, solid, apex a little anterior, the slopes 

 straight ; surface finely closely and evenly radiately striated, white 

 with purplish or brownish rays ; the rays usually 10 in number, 

 articulated with darker spots which are often angular. 



Inside white, showing the rays faintly; the central area light 

 chestnut or outlined with light chestnut, edge of the shell smooth, 

 articulated with white and chestnut. 



Length 16, breadth 12, alt. 7 mill. 



Length 20, breadth 15*, alt. 8 mill. 



Island of Reunion. 



P.profunda DH., Moll. Reunion, p. 44, t. 6, f. 15, 16, 1863. 



A small conical species, nearly smooth, the radiating striae being 

 quite fine. The rays are more obvious on worn examples. The 

 central area is not calloused. It has very much the appearance of 

 an Acmcea. 



Var. MAUKITIANA Pilsbry. PI. 65, figs. 97, 98, 99. 



Shell thicker, heavier, more elevated ; dull white with reddish 

 rays, which are not visible within, and only faintly visible at the 

 edge, which is minutely crenulated; basal side-margins slightly 

 curving upward ; radiating striae of the surface coarse, unequal. 

 Central area of the interior having an orange-tawny callus. 



Length 21, breadth 17, alt. 11 mill. 



Mauritius. 



H. GARCONI Deshayes. PL 66, figs. 100, 101. 



Shell ovate, little narrowed in front, conical ; vertex acute, sub- 

 central ; ornamented with small granulous radiating striae ; blackish- 

 brown, vividly pearly inside, toward the apex whitish. (Z>/i.) 



Regularly oval, conoidal, the summit elevated, pointed, very 

 slightly directed forward, situated at the front two-fifths of the 

 length. From the apex radiate a great number of very fine, regu- 

 lar, rather equal riblets, which bear long, obtuse granules. The 

 margins are simple and sharp. The interior is lined with very 

 bright nacre of a whitish-brown, the central callus quite large, 

 white, sharply defined by the muscle-scar. The shell is thin, semi- 



