SCALARIA. 205 



tensity. The raised sculpture has, for the most part, 

 a more fulvous cast. Exotic specimens are more fre- 

 quently of an uniform chocolate-brown. About twelve 

 depressed ribs, that instead of uniting in one continuous 

 row with those of the previous or following volutions, 

 spread out laterally above, run almost perpendicularly 

 across the whorls, and reach the extreme base, which 

 is not girt by any spiral belts or sulci. These cross- 

 bars, as they are often termed, are simple, round-topped, 

 and principally narrow and quite smooth, but mingled 

 with them are also present so"me broader varices, that, 

 from the longitudinal wrinkles upon them, look as though 

 they were composed of two or more united costellae. The 

 broad interstices, although apparently smooth to the un- 

 assisted eye, exhibit most delicate and closely disposed 

 spiral striulse, when examined by a lens of the most 

 moderate power. The number of turns ranges from twelve 

 to sixteen, the former is the more frequent ; they are 

 rather short (their breadth being nearly twice their 

 height), but little oblique, enlarge gradually but per- 

 ceptibly, are moderately rounded but not sw^ollen, and 

 are closely connected to each other, their sutures not 

 being excavated as in coimmmis, &c. The aperture is 

 rounded, oval, longer than broad, occupies about two- 

 ninths of the total length, and rather more than half 

 the basal diameter ; it is neither oblique nor much pro- 

 jecting, and its peristome is considerably and nearly equally 

 thickened throughout. The average length of J3ritish 

 specimens does not exceed an inch and a half, and the 

 breadth half an inch. Turton, however, mentions one 

 which measured two inches and a half, by three-quarters 

 of an inch. Mediterranean examples are much smaller 

 and have usually only nine or ten cross-bars. 



