Description of the Fossils in the older Deposits of the Rhenish Provinces. 363 



Folds twenty-four in number, surrounding a very open umbilicus in which are seen all the volu- 

 tions. Aperture subpentagonal, its width equal to a third of the total diameter. 

 This small species is distinguished from the E. nodosus, Sow., by its stature, which is always much 

 less, and by its folds instead of tubercles. The number of these folds is double that of the tubercles, 

 and further, they radiate toward the umbilicus, while in Sowerby's species they are elongated even in 

 the direction of the involution. This shell might then be regarded as a true Solarium, since it possesses 

 the only character which distinguishes this latter genus from Euomphalus. 

 Paffrath ; rare. Newton. Tournay, mountain limestone. 



3. Euomphalus IcBvis, nob. Helicites prisons, Schlot. Petref., PI. X. f. 1. Tab. nost., XXXIII. f. 8, 8 a. 

 Shell subdiscoid. Spire somewhat elevated, composed of five volutions, subcarinated above and 

 rounded beneath. Suture simple, rather deep. Striae of growth very fine, close-set and slightly 

 undulated. Umbilicus rather wide, showing the interior of the spire. Aperture quadrilateral, 

 rounded. Shell thick. 

 This shell, which seems to be related to Helicites prisons, bears the greatest analogy to certain Euotn- 

 phali of the mountain limestone. 

 Paffrath ; rare. 



4'. Euomphalus planorbis, nob.. Tab. nost., XXXIII. f. 1, 7 a. 



Shell discoid, planorbular, composed of seven rounded volutions, increasing slowly, contiguous, but 

 not embracing in young individuals, which are almost symmetrical. Suture simple and deep. Spire 

 scarcely raised above the last volution. Striae of growth numerous, radiating, simple and straight. 

 Umbilicus very open. Aperture rounded, nearly entire. 



This species approaches very near to the E. serpens of Phillips's Palseoz. Foss., XXXVI. f. 172. 



Villmar, Paffrath ; common. 



5. Evxrmphalus Serpula, de Koninck, Descrip. Anim. Foss. Belgique, Tab. nost., XXXIII. f. 9, 9 a, 9 b. 

 This shell differs from the last, of which it is perhaps only a variety, in its volutions being often sepa- 

 rated and free. Sometimes united and contiguous when young, they separate and become distant with 

 age. Sometimes the involution is continued on the same plane, but occasionally it forms an irregular, 

 more or less elevated spire. 



This Euomphalus, common enough at Paffrath, is not less so in the mountain limestone of Belgium 

 and Ireland. 



6. Euomphalus annulatus, Phill. Pal. Fos., PI. LX. fig. 172 *. Tab. nost., XXXIII. f. 11, 11 a. 



Shell discoid, planorbular, nearly flat above, excavated beneath, composed of six rounded, exposed 

 volutions, increasing slowly, and contiguous but not embracing. Regular, numerous, transverse 

 striae, set off from both sides of the suture, and rise to one-third of the surface of the volutions, 

 then subdivide into four or five much finer striae in passing over the back of the shell. Aperture 

 entire, rounded, furnished with a salient varix. A second varix may be seen, also upon the last 

 volution, at some distance from the aperture. 



This little shell is remarkable for its varices, in which it resembles certain Serpulae. 



Paffrath ; rare. Newton. 



II. Species with more or less sharp-edged angular volutions. 



7. Euomphalus qualteriatns, Bronn. Leth. Geog., PI. II. f. 1, a, b. Helicites qnalteriatus, Schlot., 



PI. XI. f. 3. Var. nob. 



