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



oblique striae, crossing the suture of the septa at a very acute angle. These striae, of which the 



impression is seen upon the cast itself, belong to the inner lamina of the shell, which is entirely 



destroyed. Edge of the septa simple. In the anterior part of the shell, which is all we possess, 



these septa are very close, and five may be counted in the height of one diameter. Siphon rather 



large, elliptical and touching the edge. 



The peculiar disposition of the striae is sufficiently characteristic of this species. It is true, the Ortho- 



cera undulata, Min. Conch., Tab. LIX., presents folds oblique to the axis, but they are much larger, less 



numerous, and inclined in the same direction as the septa. The siphon, moreover, is submarginal. In the 



O. subtrochleatus and O. carinatus, loc. cit, of Miinster, Taf. XIX. f. 6, 8, the siphon is submedian 



and median, and the folds are undulated, instead of being straight as in the O. Dannenbergii. 



There is found in the iron mines of Brilon a transversely striated species which bears the greatest 

 analogy with this. 



It is with pleasure we dedicate this species to M. Dannenberg who has so powerfully contributed by 

 his assiduous researches to make known the Palaeontological riches of the Duchy of Nassau. 

 Wissenbach ; rare. 



8. Orthoceratites Ibex, Murch. Sil. Syst. PI. V. f. 30. 



This species does not appear to us to differ essentially from the O. articulatum (PI. V. f. 31) of the 

 same author, of which the ribs are perhaps more rounded, nor from the O. annulatus of Hisinger (Lethaea 

 Suec, Tab. IX. f. 8), which is really the same as the O. annulata of Min. Conch., Tab. CXXXIII., for 

 the obliquity of the rings is in most cases merely caused by accidental compression. It is true Mr. J. 

 Sowerby now makes his O. lineolatum of this last, reserving the old name for the species called O. annu- 

 latum in the Sil. Syst. As to the O. anriulatum, Phillips (Geol. Yorks., Part 2, PI. XXI. f. 9, 10. O. annu- 

 lare, reference to Plates), it appears to be much shorter and more conoidal than the preceding, and the 

 O. annulatum, Murch. (Silur. Syst., PI. IX. f. 5, p. 632 and note), which approaches the O. undulatum, 

 Hisinger (not Min. Conch.), differs principally in its transverse festoons and its longitudinal striae. The 

 species which we indicate in the slates of Wissenbach is also distinguished from the O. scalaris, Goldf., 

 in being much more elongated ; its ridges are sharp instead of being flattened, and the spaces which 

 separate them, more considerable. 



Wissenbach ; rare. 



9. Orthoceratites calamiteus, Miinst. Beitrage zur Petrefact., Heft i. PI. XVII. f. 5. p. 36. ; Heft iii. 



p. 102. O. cingulatus, Goldf., Bonn Museum. 



We refer to this species, but with some doubt, in consequence of its bad state of preservation, a frag- 

 ment of an Orthoceratite covered with transverse rings, very finely striated, as well as the intervals which 

 separate them, and with narrow longitudinal ridges, which are more salient as they cross over the rings. 

 Siphon median. 



In consequence of the presence of the striae, and the transverse and longitudinal ridges, this species 

 seems to be intermediate between the Orthoceratites which present only one or the other of these cha- 

 racters. 



Eifel, Chimay, Fichtelgebirge, Refrath, Brilon. 



10. Orthoceratites anguliferus, nob.. Tab. nost., XXVII. f. 6. 



Shell of an elongated cone shape, smooth, but covered with chevrons or zigzag coloured marks, of 

 which the acute angles correspond regularly from the upper to the lower end of the cone. These 

 angles, about 18 in number, are alternately turned toward the summit and the base. The little 

 brown bands which form them are half a millimetre in width, and are separated by an uncoloured 

 space of nearly equal width. If a line be passed through the successive summits of the upper or 



