514 trochidjE. 



cinerarius, but the more scalariform mode of its gyration 

 will readily distinguish it. It has been conjectured to be 

 identical with the T. Nassaviensis of Chemnitz (Conch. 

 Cab. vol. v. pi. 171, f. 1676. — T. patholatus, Gmel. Syst. 

 Nat. p. 3574), but even if so, — a conclusion certainly not 

 warranted by the figure, — the extremely imperfect definition 

 of that shell would invalidate the claim of priority. 



The general shape ranges from rather obtusely conic 

 to orbicular conoid ; the base is generally more or less 

 flattened, rarely a little convex near the mouth, and mode- 

 rately shelving ; the lateral outline is somewhat arched, 

 and more or less scalariform. The shell is small, rather 

 strong for its size, sometimes opaque, sometimes very 

 slightly diaphanous, more or less dull, and of a pale ash- 

 colour, variegated with more or less interrupted oblique 

 and wavy lines of chestnut, brown, or greyish brown, 

 which often become partially or entirely obsolete upon 

 the base ; in certain individuals, the continuity of the 

 lines being no longer perceptible, the surface appears spi- 

 rally articulated with rather distant coloured minutely 

 oblong dots ; in others there are additional squarish spots 

 below the sutures. Both the upper and lower surfaces are 

 encircled with fine and numerous raised lines, which are 

 generally fewer, coarser, and more distant in the northern 

 examples. There are frequently, besides, some fine spiral 

 striulse in the interstices, and the whole shell is microsco- 

 pically traversed by obliquely longitudinal and most densely 

 disposed wrinkles. There are six volutions, which increase 

 with moderate quickness ; the apex is tolerably acute ; 

 the next whorls more or less rounded ; the two or three 

 last are narrowly angulated below the suture, and then 

 become flattish and but little shelving; there is often, 

 besides, a very slight but diffused refusion upon the body- 



