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



1 . Natica margaritifera, nob., Tab. nost., XXXIV. f. 4, 4 a. 



Shell ovoid, with a very short spire composed of four volutions, the last alone forming nearly the 

 whole of the shell. Upper volutions ornamented with two or three rows of granulations between 

 which new rows become interposed as the shell increases, so as to present as many as twelve upon 

 the last volution. Six or seven, larger than the others, maj'^ then be reckoned, between which the 

 smaller are placed ; or they may be all of tlie same size and equally distant. Suture subcanalicu- 

 lated. Aperture semilunar, oblique to the axis, rounded at the base and contracted at the summit. 

 Left lip entirely covered by a callosity which hides the umbilicus and reaches to the upper angle. 

 Right lip simple. Height, 10 millim.; diameter, 8. 



Paffrath ; rare. 



2. Natica subcostata, nob. Nerita subcostata, Goldf. Bonn Mus. Tab. nost., XXXIV. f. 5, 5 a, var. a, f. 6. 



Shell subglobular, spire short, composed of five or six volutions, flattened toward the middle part, the 

 last very large, composing nearly the whole of the shell. Suture rather deep. Spire covered with 

 greater or smaller, close-set and oblique folds, which commence at the suture and bifurcate on 

 reaching the middle part of each volution : upon the last they are prolonged as far as to the cal- 

 losity of the left lip. In some individuals these folds become decided ribs which do not bifurcate, 

 and between other supplementary ribs which accompany them to the base. There are three 

 transverse rows of brown spots which are the remains of the colouring matter of the shell. Aper- 

 ture large, semilunar, oblique to the axis, rounded at the extremities. Left lip flattened, com- 

 pletely covered, together with the columella, by a callosity which unites with the right lip at the 

 upper angle. Base of the aperture rounded and slightly effuse. Right lip dilated. 

 Var. a. fig. 6. {Nat. nexicosta, Phill. Pal. Fos., PI. XXXVI. f. 174.) Shell much more globular than the 

 preceding. Volutions regularly rounded. Aperture more dilated. Callosity of the left lip narrower. 



We do not think that the Murex harpula, Sow. (Min. Conch., PI. DLXXVIII. f. 5), belongs to this 

 species, as Bronn seems disposed to admit. Mr. Phillips unites both under the name of 3Iacrockeilus 

 harpula (loc. cit. XXXIX. f. 197, p. 105), but his figure does not appear sufficiently complete to enable 

 us to pronounce with certainty on the resemblance. 

 Paffrath ; common. Devonshire. 



Pileopsis cassideus, nob., Tab. nost., XXXIV. f. 10, 10 a. 



Shell of a very short conical form, very oblique. Summit pointed, recurved, and extending beyond 

 the base. Aperture subelliptical, transverse. From the summit sets off' a salient keel which de- 

 scends to the base, where it produces an indistinct ridge {pincement peu prononce). 



Grauwacke of Kemmenau ; very rare. 



Orbicula ? 



Numerous Orbiculae are found in the Kemmenau beds, but not suflSciently well-preserved to be de- 

 scribed. They attain dimensions much greater than any of the species yet known belonging to the 

 older beds. 



Kemmenau, Le Faou, Brittany. 



Lingula • ? 



A species related to L. cornea, Sow. (Sil. Syst., PI. Ill . f. 3). 

 Lethmate ; rare. 



1. Terebratula concentrica, de Buch, Mem. de la Soc. Geol. de France, t. iii. p. 214. Bull. id. xi. PI. 



n. f. 1. 



