Archive image from page 179 of Devonian fishes of Iowa (1908). Devonian fishes of Iowa . devonianfishesof00east Year: 1908 186 IOWA GEOLOGICAL SURVEY toral limb. As shown by Furbringer, the two opercular plates of Neoceratodus are sometimes fused into a single piece, and this fact acquires significance on recollecting that only a single oper- cular element is known to occur in most Arthrodires. Jaekel is the only investigator who has reported the presence in Coccos- teus of two opercula, the normal number among Dipnoans, and it would be interesting to have this observation confirmed. Genus co
Archive image from page 179 of Devonian fishes of Iowa (1908). Devonian fishes of Iowa . devonianfishesof00east Year: 1908 186 IOWA GEOLOGICAL SURVEY toral limb. As shown by Furbringer, the two opercular plates of Neoceratodus are sometimes fused into a single piece, and this fact acquires significance on recollecting that only a single oper- cular element is known to occur in most Arthrodires. Jaekel is the only investigator who has reported the presence in Coccos- teus of two opercula, the normal number among Dipnoans, and it would be interesting to have this observation confirmed. Genus coccosteus Agassiz. Of the four American species that have been referred to this genus, only one, C. canadensis Woodward, is satisfactorily known, the others being represented by detached plates exclu- sive of the headshield. To C. occidentalism described in the first instance by Newberry from the Onondaga limestone of Ohio, are possibly to be referred a few isolated fragments occurring in the Middle Devonian of New York State, and it has further been surmised by the original author that the dental plates known as Liognathus spahdatus belong to the same species. No illustra- tion has been published of the form described by Cope from the Chemung of Leroy, Pennsylvania, under the name of C. macro- mus, but it is said to be distinguished from C. occidenUxlis by its coarser tuberculation. A restoration of the type species of this genus is given in the accompanying text-figure 26. Fig. 26. Fig. 26. Coccosteus decipiens Aga8siz. Lower Old Red Sandstone; Scotland. Lateral aspect restored by Smith Woodward, in part alter Traquair. x i. TThe caudal fln is here conjecturally represented as heterocercal, for which there is no evidence; it may be re- garded with even greater probability as having been diphycercal.] Coccosteus rnacromus Cope. 1892. Coccosteus rnacromus E. D. Cope, Proc. Amer. Phil. Soc. 30, p. 225. 1907. Coccosteus rnacromus C. R. Eastman, Mem. N. Y. State Mus. 10, p. 116.
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