MANUAL OF THE MOLLUSCA. 
Shell like Cecwm, smooth; aperture simple, acute; apex closed 
by a mamillated plug; operculum, convex. 
Distribution, 2 species. Europe, West Indies, Mazatlan. 
MEIOcERAS, Carpenter. 
Etymology, meion, rather small; ceras, horn. 
Young shell spiral or flat; adult somewhat inflated; aperture 
oblique; operculum spiral, scarcely concave. 
Distribution, 3 species. West Indies. 
STREBLOCERAS, Carpenter, 1858. 
Hiymology, streblos, twisted; ceras, horn. 
Shell with the spire not decollated, no plug formed ; nuclear 
whorls orbicular, perpendicular to the plane of the adult; the - 
plane of growth is flat, asin Cecum, but some examples haye a 
slight twist, forming an approach to Meioceras. 
Fossil, 4 species. Eocene. Hampshire, Paris. 
FAminty V.—TURRITELLIDA* 
Includes TURRITELLA, PRoTO, MESALIA, and 
CASSIOPE, Coquand, 1865. 
Synonym, Omphalia, Zekeli, 1852 (non Omphalius, Philippi, 
1847). 
Example, Turritella Renauxiana, D’Orbigny. 
Shell thicker, and with more rapidly increasing whorls than 
in Turritella, often pupiform; aperture rounded, continuous ; 
outer lip notched or sinuated by an impressed furrow, which 
winds round the last whorl; columella usually distinctly um- 
bilicated. 
Distribution, 32 species. Cretaceous. Europe, India, and 
America. 
[Faminy ScALARIADZE | 
Includes ScALARIA and the sub-genera Hglisia, Pyrgiscus, and 
Cirostrema, Morch. 
Shell solid, varices irregular, whorls generally cancellated. 
CocHLEARIA, Braun. 
Synonym, Chilocyclus, Bronn. 
* See p. 248. T See p. 250. 
2¢, 
