362 Viscount d'ARCHiAc and M. de Verneuil's 



of growth. Broad, slightly prominent ; radiating and undulating folds may also be seen upon the base 

 of the last volution. Some individuals, moreover, show obsolete stria; upon this part of the shell. 



We have also given a figure of one of the numerous varieties of this species (PL XXXIII. f. 4- a.). It 

 is remarkable for the great elevation of the spire. The volutions are less flattened on the upper part 

 than in the other varieties. The lines of growth are thicker and the band is placed lower. Perhaps these 

 characters may at some future time cause this shell to be regarded as a distinct species. 



Although very plentiful in the limestones of Paffrath, the PI. delphinuloides is rare in all other loca- 

 lities. The cast figured at PI. LVII. f. 17. of Messrs. Sedgwick and Murchison's memoir on Devonshire 

 (Geol. Trans., vol. v.) seems to be a small individual of our turriculated variety. TheP/. vittata (Phill. 

 Geol. Yorks., Part 2, PI. XV. f. 24) might also perhaps be regarded as a variety between the two that we 

 have figured, as well as the Helix cirriformis, Sowerby (Min. Con., PI. CLXXI. f. 2. Pleurotomaria, 

 Index). 



Paffrath ; very common ; the limestones of Devonshire and mountain limestone of England. 



EUOMPHALUS. — I. Species with rounded or very slightly carinated volutions. 



I. Euomphalus Goldfussii, nob. Euomphalus spinosus, Goldf. Bonn Mus., Tab. nost., XXXIV. f. 1, 

 1 <z, 2, 2 a. 

 Shell discoid, flattened above, deeply excavated beneath. Six rounded volutions, very slightly convex 

 and nearly smooth above. In the middle numerous, oblique, rather irregular striae in the first place 

 run forward and then backward to reach the inner suture. In passing over the lower plane of the 

 volutions these strias are interrupted or modified by irregular folds. These latter produce unequal 

 tubercles, inclined forward, sometimes spinose, sometimes pliciform, and 10 or 12 in number 

 upon the base of each volution and placed at equal distances from the inner suture and the outer 

 edge. In the umbilicus the last volution but one is also armed with spiniform tubercles placed 

 against the suture. The transverse striae are usually distinct and very regular upon the first 

 volutions, at the bottom of the umbilicus, and near its top they often unite in bundles and join the 

 tubercles. The latter become gradually slighter and disappear altogether upon the first volutions. 

 Upon the middle part of the volutions may also be observed zigzag striae which cross the preceding 

 and cause a reticulated or finely granular character, which is still more distinct in young individuals 

 without tubercles. Umbilicus very open, showing all the volutions. Aperture round, scarcely 

 modified by the penult volution and occupying two-fifths of the total diameter. 

 In young individuals (fig. 2, 2 a.) the decussated striae are more distinct both above and beneath 

 each volution than in the adult, in which they often disappear even from above as the tubercles are de- 

 veloped beneath. In the young shell the involution is almost symmetrical and on the same plane, but 

 with age the increase in the height is made almost exclusively downwards, of which the result is a very 

 large umbilicus without great elevation of spire. 



This fine species is distinguished from E. nodosus (Sow. Min. Con., Tab. XLVL), by the absence of 

 the keel from the upper part of the volutions, by the form of its spinous folds, and by the striae with 

 which its surface is ornamented. It is equally distinguished from the E.bifrons, Phillips (Geol. Yorks., 

 Part 2, PI. III. f. 4.), by the position of its tubercles, which are placed on the lower instead of the upper 

 side of the volutions. 



Lustheide, Paffrath ; rare. 



2. Euomphalus Labadyei. Tab. nost., XXXIII. f. 6, 6a, 6b. 



Shell discoid, composed of five volutions slightly carinated above and regularly plicated beneath. 



