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



Shell discoid, subumbilicated, volutions depressed, their inner edge inclined toward the suture at an 

 angle of 45° ; the lateral portion then describes a slight but regular curve, continuing to the bacli 

 which is sharp-edged. Four visible volutions are enveloped to about three-fourths of their width. 

 Numerous, unequal striae set off from the suture and taking a direction obliquely forward, begin to 

 turn back toward the middle of the sides. [The bad condition of the specimen prevents us from 

 determining what their form is up to the back.] Dorsal lobe rather larger than deep; dorsal saddle 

 rounded. First lateral lobe very narrow, lanceolate, sharp, twice as deep as the dorsal lobe. First 

 lateral saddle rounded, rising to double the height of the dorsal saddle, and occupying rather less 

 than a third of the side of the shell. Second lateral lobe as deep and almost as narrow as the first. 

 Second lateral saddle rounded, rising to the height of the dorsal saddle and terminating at a third, 

 shallow lateral lobe which limits the inner edge and ends at the suture. 

 This species, remarkable for its size, as well as for its form and the number of its septa, of which we 

 liave counted forty in a single volution, was first described by De Buch and afterwards by Bronn ; but 

 the descriptions, and the figures especially, of these authors, were so incomplete, that we have endea- 

 voured as much as in our power to complete the knowledge of this fine fossil. 

 Ilefrath ; very rare. Eifel ; some fragments. 



11. Goniatites Buchii, nob. Tab. nost., XXVI. f. 1, 1 a, 1 6. Var. a, f. 2, 2 a. 



Shell discoid, umbilicated, volutions flattened upon their sides. Back rounded ; dorsal lobe narrow, 

 lanceolate and shallow. Dorsal saddle rounded. First lateral lobe lanceolate, sharp and double the 

 size of the dorsal lobe. Lateral saddle rounded, rising much higher than the dorsal saddle and oc- 

 cupying half the side of the shell. Second lateral lobe lanceolate, descending nearly as low as the 

 first. Although in our specimen this part does not show distinctly the termination of the septum, it 

 is probable that there is a third lateral saddle upon the inner edge and perhaps a third lobe, after 

 which the septum continues backward to unite with the suture. In the figure the third saddle only 

 is shown. 

 Var. a, f. 2, 2 a. This variety is known by very distinct arched folds upon the middle of the back which 

 become less distinct toward the edges. A portion of the shell being preserved shows that it was orna- 

 mented with fine and very close-set strias, setting off from the suture, turning backward and then rising 

 again abruptly forward toward the edge of the back. They then curve backward again and form a deep 

 sinus which occupies its entire breadth. The arched folds are independent of these striae and appear 

 only to exist under the striated shell and perhaps only on that anterior part of the shell which is desti- 

 tute of chambers. The variety appears also to remain smaller than the type of the species. 



At first sight the G. Buchii might be regarded as intermediate between the G. intermedius and G. 

 carinatus of Beyrich, but in the first place, it differs from the former in its more depressed general form 

 and in its more flattened sides ; from G. carinatus in its simple and rounded back, and from both in its 

 simple and narrow dorsal lobe, a character which, added to its form, to the disposition of its lobes and 

 saddles, as well as to the number of its chambers, brings it near to G. Hoeninghausii. 

 Oberscheld; very common. 



C. Four lateral lobes. 



1 2. Goniatites costatus, nob. Tab. nost., XXXI. f. 1 , 1 a. 



Shell flattened. Volutions numerous, rounded, half exposed, ornamented with simple, elevated ridges, 

 twenty-four upon each volution ; these ridges set off' from the inner edge, occupy two-thirds of the 

 side, then turn forward and become weaker toward the dorsal channel where they are no longer 

 seen. Back wide, rounded, edged by two shallow channels, which become attenuated and disappear 

 from the last volution of large individuals. Dorsal lobe apparently deeply divided. The artist has 



