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



proach the fissure, and forward again after passing it. The little band presents arcuated striae, 

 whose concavity is turned forward. Slightly undulated folds, granular at their commencement, are 

 seen upon the base of the last volution. Aperture oblong, differing probably but little from those 

 of the preceding species. 

 This shell differs from the M. bigranulosa, by its much greater stature, by the size of its tubercles and 

 the form of its volutions which are excavated instead of being flat ; and lastly, by its broad and flat band, 

 which is narrow and raised in the preceding species. 

 Lustheide ; very rare. 



7. Murchisonia tricincta, nob. Schizostama triciiicta, Miinst., Beitr. z. Petref., iii. Heft, PI. XV. f. 14. 



Var. Tab. nost. XXXII. f. 13, 13 a. 



This shell differs from that figured by Count Miinster, in the keel being placed near the base of each 

 volution, instead of dividing them into two equal parts ; thus the volutions are, as it were, imbricated. 

 Further, there is between the keel, which is double, and the suture, a third thread, which is not seen in 

 the type of the species ; and lastly, our shell appears to attain a much greater dimension than that of 

 the limestones of Elbersreuth. 



Villmar ; very rare. 



8. Murchisonia tcBniata, nob. Turritella tmniata, Phill. Geol. of Yorksh., Part 2. PI. XVI. f. 7. 



We have some doubt in referring to this species, belonging to the mountain limestone of Bolland, a 

 worn-out shell brought from Gronau. 



Turritella ? 



To this genus we refer a not well-characterized cast of a shell which we found in the slates of Wissenbach. 

 Turbo squamiferus, nob., Tab. nost., XXXII. f. 14, 14 a. 



Shell conoidal, subturriculated, composed of six angular volutions each ornamented with two rows or 

 raised pliciform scales, one of which, very prominent, is on the medio-superior part of the volutions, 

 and the other, which is composed of finer and more numerous scales, is at the base. Suture simple. 

 Two narrow and sharp keels are also seen at the lower part of each volution ; one of these, fre- 

 quently plicated, forms the outer edge of a very small umbilicus, and ends at the base of the right 

 lip. The whole shell is covered with lines of growth, more distinct on the last volutions than on 

 the first. Aperture round, its edges disjoined at the upper part. Left lip a little reflected, and 

 uniting with the right lip by a continuous curve. Height, 28 millim. ; diam. of the last volution, 20. 



Limburg. 



Monodonta purpurea, nob.. Tab. nost., XXXII. f. 15, 1 5 a. 



Shell trochiform, composed of four volutions, of which the last is very large and constitutes alone 

 two-thirds of the shell. Volutions convex, rounded, covered with from ten to twelve rows of gra- 

 nulations, disposed very regularly and reaching to the umbilical callosity, near to which the striae 

 are finer and more close-set than upon the last volution. Aperture semilunar, very oblique to the 

 axis. Left lip wide, very much flattened, and entirely covered by a callosity which rises to the 

 upper angle. This lip is furnished with a rather strong tooth placed at the top of the umbilicus. 

 The latter is hidden by the callosity, but a slight depression points out its place. Columella arcu- 

 ated and united to the right lip by a regularly rounded curve. Height, 22 millim. ; diameter of the 

 last volution, 18. 

 This shell is remarkable for the flattening of the left lip, very like what is observed in the Purpura, 

 and for the absence of any truncation of the columella, which is united continuously Mdth both lips. It 

 could be referred to Grateloup's genus Neritopsis. 

 Paffrath ; rare. 



