Description of the Fossils in the older Deposits of the Rhenish Provinces. 341 



given to the drawing of tliis part of the chamber more precision than the state of the specimen 

 justifies. There are four tongue-shaped lobes, which diminish in depth as they approach the suture. 

 Saddles rounded. Septa twelve to each volution, leaving between each the space occupied by a rib. 



This Goniatites is one of those which by the general form remind us most of the true Ammonites, 

 particularly of those of the family of the Arietes. 



Collected by M. Dannenberg at Eibach near Oberscheld ; rare. 



13. Goniatites costulatus, nob. Tab. nost., XXVI. f. 3, 3 a, 3 b. 



Shell flattened. Volutions four or five, half-exposed, depressed toward their middle part. Inner edge 

 nearly straight and slightly excavated beneath. Back wide, flattened, bordered by two narrow and 

 shallow channels. Twenty-eight to thirty simple ribs set off from the suture, take a backward di- 

 rection across half the side, where they are more prominent, then rise again toward the dorsal chan- 

 nel, becoming attenuated so as to disappear completely upon the outer edge of each channel. Be- 

 sides these ribs, in those parts where the shell has been well preserved, there are fine undulated strise, 

 which after going forward to the dorsal channels, turn backward to form a sinus which occupies the 

 whole width of the back as in the G. paucistriatus. 

 This species appears to be related to the G. costatus, although we are not acquainted with its lobes ; 

 but it is distinguished by the form of the ribs, which are flexuous, instead of being nearly straight as in the 

 Am,monites of the family of Falciferi, and commence at the suture instead of setting off" only from its inner 

 edge : they are also more numerous than in G. costatus. Moreover, the back is almost flat, and the chan- 

 nels slightly marked, while in the preceding species the back is round, the channels are wide, and the 

 general form of the volutions also more rounded. 

 From the iron mines of Brilon ; rare. 



14. Goniatites latestriatus, nob. Tab. nost., XXVI. f. 5, 5 a. 

 Shell flattened, composed of from seven to eight half-exposed volutions, increasing slowly, and regularly 

 rounded from the suture to the back, so that the greatest altitude is at an equal distance from both 

 or at the middle of the side. Back round, bordered on each side by a shallow channel. Fine, simple 

 striae, distant from each other about a millimetre upon the last volution, set off" from the suture, 

 rise straight across half the side, then turn forward to the dorsal channel, whence they turn abruptly 

 backward to form a deep and rounded sinus which occupies the whole width of the back. Between 

 each of these principal striae may be seen two or three others, extremely delicate, and which have 

 not been expressed in the figure. 

 This species, of which we know neither the septa nor the siphon, resembles certain ClymenicE de- 

 scribed by Count Munster, and may indeed be related to G. solaroides of de Buch, which appears to be 

 a Clymenia. 



From the iron mines of Eibach near Dillenburg ; rare. 



III. Dorsal lobe divided. 



A. A single lateral lobe, generally rounded, rarely sharp, and without a dorsal saddle. 



While with Beyrich we place the species composing this group with those which have a truly divided 



dorsal lobe, we must remark, that it would perhaps be more rational to call the deep and cyathiform lobe 



which is on the side of the shell on each side of the back, the lateral lobe ; the broad saddle, which 



spreading round over the sides occupies more than half of them, the lateral saddle ; and to leave these 



species among the Goniatites with a simple dorsal lobe. In the latter the dorsal lobe is small and placed 



nearly at an intermediate height between the lower part of the lateral lobe and the summit of the lateral 



saddle, a disposition which may be observed in G. Hcemnghausii. This mode of arrangement would 



also secure the advantage of leaving all the Goniatites with a divided lobe in the Carboniferous System. 



VOL. VI. SECOND SERIES. 2 Y 



