THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTOEY. 



[FIFTH SERIES.] 

 No. 29. MAY 1880. 



XXXIII. — On the Teleostean Affinities of the Genus 

 Pleuracanthus. By James W. Davis, F.G.S. &c. 



I PURPOSE in the following remarks to consider certain cha- 

 racteristics in a group of fishes now extinct, but whose fossil 

 remains are found imbedded in the shales and coals of the 

 Carboniferous series of rocks and in the marl slate of Permian 

 age occurring in some parts of Germany. In the latter the 

 fishes are found well preserved and more or less perfect. The 

 anatomy of the fish and the relations of its various parts to 

 each other are clearly defined. In the English Coal-measures, 

 however, the fish has not been preserved so perfectly, and, as 

 a rule, the spines and teeth are found generally distributed 

 where fish-remains have been discovered to exist, but the 

 remaining parts of the skeleton are wanting. The cannel 

 coal between Bradford and Wakefield has yielded some spe- 

 cimens of the bones of the fish, in addition to a large and 

 varied collection of spines and teeth. Prof. Agassiz described 

 the spines of these fishes, and named them Pleuracanthus and 

 Orthacanthus • and the teeth he also described, and designated 

 Diplodus. The continental specimens were first described in 

 1847 by Dr. Goldfuss of Bonn, as Orthacanthus Dechenii. 

 A year later Prof. Beyrich wrote a treatise on the same fish, 

 naming it, however, Xenacanthus Dechenii. In 1855 Sir 

 Philip Egerton pointed out that the spine Pleuracanthus and 

 the Diplodus -teeth belonged to the same genus of fish, 

 Ann. & Mag. N. Hist. Ser. 5. Vol. v. 24 



