380 CALLIOSTOMA. 



sculpture, the one nearest the pillar thickened and raised at its ter- 

 mination The nucleus is sinistral. (Dall.) 



C. TIARA Watson. PI. 17, figs. 29. 



Shell small, 'conical, high-spired, flatly rounded on the base, 

 sculptured, white, dull on the surface, with a bright nacreous gleam 

 shining through. Sculpture : spirals on the upper part of the last 

 whorl there are two rows of tubercles, the first and weaker is close 

 up to the suture ; the second is a little lower than the middle, and 

 its tubercles are strong. Of these there are on each row twenty to 

 twenty-five ; they are scarcely connected by a spiral thread. The 

 periphery is sharply angulated and defined by an expressed and 

 tubercled carina, the tubercles of which are hardly so strong as those 

 of the second row above, which from its larger points projects quite as 

 much as the carina. On the base there is an infra-carinal furrow 

 and three or four sharpish, equally parted, faintly tubercled, spiral 

 threads, the innermost of which is most distinctly tubercled, and de- 

 fines the umbilical depression. Longitudinals the apical whorls, 

 except the embryonic one, are crossed by high, sharp, slightly oblique 

 ribs ; but these on the latter whorls break up into tubercles, between 

 which on the different rows there is a slight irregular connection by 

 flattened ridges, which are oblique, interrupted, and on the base 

 sinuous. Besides these, the surface is roughened by minute wavy 

 irregular lines of growth. Color white, with a translucent layer 

 of porcelaneous glaze over brilliant pearly nacre. Spire high, apex 

 small, flattened, with the minute inflated 1 1 embryonic whorl rising 

 a little exserted on one side. Whorls 7, projecting out squarely be- 

 low the suture, flattened in the middle, protuberant at the second 

 row of tubercles, and slightly contracted above the carina ; at the 

 cariua sharply angulated. The base, which is flatly rounded, has a 

 narrow flattish margin, and in the middle a slight umbilical depres- 

 sion, in the center of which is a minute umbilical hole almost covered 

 by the pillar-lip. Suture linear. Mouth scarcely oblique, and very 

 slightly inclined out from the axial line, squarish, but rounded on 

 the base and at the angles a little broader than high, nacreous with- 

 in. Outer lip not thin, with a slight callus just within it; it is 

 slightly sinuated on the base at the outer corner. Pillar-lip, on 

 leaving the body, bends over very flatly so as to cover the umbilicus, 

 after which it curves round to the left; it has a very blunt tubercle 

 in the middle, is a little reverted, and has a very slight furrow be- 



