364 Viscount d'ARCHiAC and M. de Verneuil's 



We regard as a simple variety of this species a shell which only differs in its less salient spire, in its 

 less sharp external edge, and in its aperture, which tlie more rapid increase of the last volution renders 

 higher. 



Refrath ; rare. 



8. Euomphalus trigonalis, Goldf. Bonn Mus. Solarium Petropolitanum, Pander, I. f. 3, XXVIII. f. 14, 



p. 150. Tab. nost., XXXIII. f. 10, 10a. 



Shell flat or slightly concave above, subconoidal beneath, composed of five volutions, the first of 

 which are rounded and convex, and form a very low spire, and the last, which is very large, con- 

 stitutes nearly the whole of the shell. It is divided by a rounded keel which reaches the level of 

 the spire and limits the upper and concave part of this last volution ; the other part, which forms 

 a right angle with the latter, is prolonged and rounded beneath toward the base. Suture deep and 

 channelled. Aperture forming an elongated curvilinear triangle. 

 Although we have only incomplete casts of this shell, which bears a certain analogy with Helicina 

 cxpansa (Min. Con., PL CCLXXIII. f. 1-3. Rotella Index), we have mentioned and figured it on account 

 of its singular form. Some casts have a brilliant blackish covering. 

 Paffrath. 



9. Evamphalus Schnurii, nob., Tab. nost., XXXIV. f. 1,1 a, 1 b. 



Shell discoidal, planorbular, almost flat above, very widely excavated beneath, and composed of five 

 contiguous, but not embracing, volutions. Volutions ornamented with two very salient keels, one 

 at the upper part, and the other limiting the base of each volution. Very fine, close-set striae radiate 

 from both sides of the suture, passing over the keels and producing there a row of rather indistinct 

 but regular granulations. Upon the back of the shell these strias are still finer and inclined back- 

 wards. Upon the first volutions may be remarked a third central keel, which corresponds to the 

 suture of the volutions which cover it. Aperture subpentagonal, wider than high, not modified 

 by the penultimate volution. 

 Although the striae do not continue regularly from the suture to the base of the volutions, but are 

 inflected a little in passing over the two keels, we do not think there is ever any true fissure in the right 

 lip, or that this shell could be placed in the genus Schizostoma. Besides, it has a certain analogy with 

 Euomphalus Catillus (Sow. Min. Con., Tab. XLV. f. 3, 4.), which in our opinion is not a true Schizostoma. 

 The E. Schnurii differs from E. Catillus in the form of its volutions, which may be ascertained by com- 

 paring the aperture of the two species. The aperture of E. Catillus is triangular and higher than it is 

 wide, which is precisely the reverse in E. Schnurii, in which moreover it is pentagonal. 

 Eifel ; rare. 



1 . Schizostoma radiata, nob. Euomphalus radiatus, Goldf. Bonn Mus., id. Phil. Pal. Fos., PI. LX. f. 171*. 

 Tab. nost., XXXIV. f. 3, 3 a, 3 b. 



Shell sinistral, planorbular, concave on both sides, of five volutions (not embracing), slightly convex 

 above, but much more developed beneath. There are two keels, the superior of which is very 

 distinct and forms a sort of circular, thin and sharp-edged crest upon the last volution ; the inferior 

 is rounded and placed on the edge of a very open umbilicus. Suture deep. Above, the volutions 

 are ornamented with numerous regular folds, arcuated forward, and prolonged by fine diverging 

 striae upon the anterior crest. Beneath, other striae, setting off from the edge of the same crest, re- 

 curve in an inverse direction, at first forward and then backward, to join the inner suture. Aperture 

 imperfectly triangular, with sinuous edges, and presenting on the external edges two pinchings 

 (pincements) which correspond to the keels. 



This shell, remarkable for its sinistral involution, is not less so for the lamellar crest with which it is 



