376 Prof, Kner on Xenacanthus Decheniif 



IT. — On Xenacanthus (Obthacanthus) Deceenii, Goldfuss. 



By Professor Knek, of Vienna. 



Reviewed by Dr. Christian Lijtken, Assistant Zoologist in the Museum of the 

 University of Copenhagen. 



AMONG- tlie many valuable papers by Professor Kner, on Recent 

 and Fossil Fishes/ the one before us deserves the particular 

 attention of palasontologists, as giving the first complete elucidation 

 of a remarkable type of fossil fishes, which had been hitherto, to a 

 great degree, misunderstood. Prof. Kner first gives an abstract of 

 the history of his subject. The genera Orthacanthis and Pleura- 

 cantlms were founded 30 years ago (1837), on isolated '' ichthyodo- 

 rulites " from the British Carboniferous System, by Agassiz, and 

 were erroneously regarded as the first indications of the existence of 

 Skates on our planet. They were found in various localities in Great 

 Britain (Dudley, Leeds, North Wales, Carluke, and Edinburgh) ; 

 and subsequently three other species were described by Dr. New- 

 berry, from the Carboniferous formation of Ohio. A singular form 

 of teeth, considered as those of a peculiar genus of Sharks, Diplodus, 

 Ag., was at the same time found in the Carboniferous slates of 

 England (Stafi*ord, Carluke, Burdiehouse), and in Nova Scotia. Ten 

 years later (1847), Goldfuss described and figured'^ a rather well 

 preserved impression of the fish itself from Euppelsdorf, in Bohemia, 

 while Beyrich (1848), published an account of the counter-part of 

 the same specimen,^ but named it Xenacanthus Dechenii, and Dr. 

 Jordan (1849) described some remains of the same type from 

 Lebach, near Saarbiick, as those of a fossil shark, called Triodus 

 sessilis} The identity of this last genus with Xenacanthus was 

 pointed out by Mr. Schnur.^ 



Meanwliile Sir Philip de M. Grey Egerton, Bart., had pro- 

 nounced the generic identity of Pleuracanthus and Diplodas (Brit. 

 Assoc. Glasgow, 1855), and soon after (1857, Annals, vol. xx.), having 

 examined several fine specimens from Klein-Neundorf, in Silesia, 

 he was able to announce that the spines of Xenacanthus did not differ 

 generically from these termed Fleur acanthus. Up to this time, how- 



^ Kner u. Hcclcel. Neue Beitrage zur Kenntniss der fossilen Fische, Osterrische, 

 1861. (Denkschriften d. Wiener Akademie). 

 Kner u. Steindachner. Neue Beitrage z. K. d. f. F., 0. 1863. {ibid). 

 Kner. XJeber einige Fossile Fische aus den Kriede-und Tertiaer schichten von 



Coman u. Podused. 1863. ("Wiener Sitzungberichte). 



Kleinere Beitrage z. K. d. f. F., 0. {ibid). 1862. 



Die Fossilen Fische der Asphaltschiefer von Seefeld in Tirol, 1866. {ibid). 



Die Fische der bituminosen Schiefer v. Eaihl in Karnthen. 1 866. {ibid.) 



Neuer Beitrage z. K. d. f. F. von Coman b. Gorg., 1867. {ibid). 



Nachtrag. zur der fossilen Fischcn von Raibl. 1867. {ibid.) 



Ueber Urthncanthiis Dechenii, Goldf., oder Xenacanthus Dechnit, Beyr., 



1867. {ibid). 



2 Beitrage z. Fauna d. rheinischen Steinkohle. 



3 Monatsberichtc d. Ak. d. W. Berlin. 



* Leonhard u. Bronn. Jahrbuch, etc., p. 843. 



* Zeitschrift d. deutschen Geologischen Gesellschaft, viii., 1856. 



