TRANSLATIONS AND NOTICES 



OF 



GEOLOGICAL MEMOIRS, 



Description of the Orthacanthus Dechenii. By Dr. Goldfuss. 



[From Beitrage zur vorweltlichen Fauna des Steinkohlengebirges. Bonn, 1847.] 



The skeleton figured* was found in a slab of reddish-coloured, slaty 

 limestone, from a bed in the carboniferous sandstone of Ruppersdorf 

 in Bohemia, and presented by its discoverer, Herr v. Dechen, Di- 

 rector of Mines, to the museum of our university. It lies on the belly 

 with the left side a little turned up, so that the right side appears 

 shortened. The tail is broken oif behind the ventral fin, and the 

 length thus far is fifteen inches Rhenish. The slab over the whole 

 outline of the animal and for an inch beyond has a red colour, so that 

 the form of the body is shown, as it were, by a shaded outline. 

 The head, the vertebral column, the pectoral and pelvic arches are 

 covered with vitreous, rounded quadrangular, granular scales {Kor- 

 nerschuppen), pushed over each other. The head has a semi- 

 circular outline, which seems also to correspond to the large opening 

 of the mouth, since on the right side numerous remains of broken 

 teeth are seen all round. Behind the probable termination of the 

 lower jaw the head suddenly contracts about a fourth. On the ante- 

 rior portion behind the obtuse snout, two conical cavities are visible, 

 which appear to open out forwards, and hence may be considered to 

 be nostrils. On the other hand, no trace remains of the cavities for 

 the eyes. A straight spine is rooted in the neck, and is 4 inches 

 7 lines long, and 3 lines broad at the root. It has no articulation at 

 the base, is smooth on the anterior surface, though slightly cracked, 

 and on the posterior side is enclosed in the stone. The vertebral column 

 shows indistinct spinous processes, whence it may be deduced that it 

 was imperfectly ossified. From it, as far down as the pelvis, nu- 

 merous, short, straight ribs proceed, which are inclined backwards, 

 and at the thin end are often bent in various directions, and seem to 

 consist of a single series of granules. The scapular arch on each 

 side is formed by a bone 5 lines broad, which is curved inwards, di- 

 rected backwards, and has a knee-shaped angle on the posterior third 

 of its outer margin. This margin is covered thus far with fin-rays 

 which are formed of two alternating series of osseous granules {Knock- 



* In tab. 5. fig. 9-11 of the above work. 

 VOL. V. PART II. D 



