BUFFALO SOCIETY OF NATURAL SCIENCES 157 



Remarks. — The genus Anodontacanthus was established by J. W. 

 Davis in 1881^" for certain peculiar spines from the Coal Measures of 

 England and Scotland, distinguished by (i) the absence of denticles 

 from the posterior margin; (2) by their straight, tapering form; and 

 (3) their subeUiptical to subcircular cross section. A second species 

 was described by Fritsch, in 1889,''^ from the Permian of Bohemia 

 (under the name of Platyacanthus ventricosus) , and a third by Hussa- 

 kof, in 1 91 1, '^2 from the Permian of Texas. The genus, therefore, had 

 a wide geographical as well as geological distribution. The present 

 species is the first record of it from the Devonic. 



These spines are probably head spines of Pleuracanth sharks, and 

 it is not siuprising therefore to find them represented in the Devonic, 

 and particularly in the Conodont bed, since teeth of three species of 

 Pleuracanth sharks (Dittodus) occur in this formation. 



From the previously known species, the present one is distinguished 

 by its very smaU size, by differences in cross-section, and by the orna- 

 mentation of incised lines, which are stronger and more irregular 

 than in the other species, and by the absence of pittings in the 

 striations. 



Genus Atopacanthus, n. gen. 



In 1 9 13 Hussakof''^ described an ichthyodorulite remarkable for 

 its very large denticles, or teeth, along one margin. The species did 

 not fit into any known genus; and since all three specimens in hand 

 were imperfect, it was thought inadvisable to base a new genus upon 

 them. In view of the large size of the denticles and the thinness of the 

 spine itself, the specimens were provisionally placed in the genus 

 Apateacanthus, sl genus known only by a unique spine from the De- 

 vonic of New York State — A. vetustus (Clarke). 



Among the specimens from the Rhinestreet Shale in the Buffalo 

 Museum, there is a spine of the same character; it throws a httle 

 light on these curious elements and enables us to frame a generic 

 definition for them. 



The specimen (fig. 54, A) is an elongated, spine-shaped element, 

 narrowly elliptical in cross-section, with three teeth preserved along 



"On Anodontacanthus, anew genus of fossil fishes from the Coal Measures; with descriptions of 

 three new species. Quart. Journ. Geol. Soc, xxxvii ,427, pi. 22, figs. 10-12. 



^ Fritsch, A.: Fauna der Gaskohle, Band 3, p. 113, pi. 86, fig. 5. 



'2 The Permian fishes of North America, in Case's "Amphibia and pisces of the Permian of North 

 America." Publ. No. 146, Carnegie Institution Washington, p. 162, pi. 26', figs. 5, sB. 



"Hussakof. L.: Description of four new Paleozoic fishes from North America. Bull. Amer. Mus. 

 Nat. Eist., xxxii, 245-250, pi. xlvii, igi3. 



