248 PROCEEDINGS OF THE NATIONAL MUSEUM. 



A second specimon (pi. 8, fig. 5), preserved in the form of an impres- 

 sion, and apparently referable to this species, is contained in the 

 United States National Museum collection. It is from the Chemung 

 of Bradford County, Pennsylvania, and agrees closely in fomi and 

 size with the type of D. angustus except that it displays one addi- 

 tional ridge near the posterior extremity, and all of the radiating 

 ridges are distinctly tuberculated. The same separation is observed 

 between the two anterior ridges as was noted by Newberry in his 

 description of the type. The characters of this species resemble those 

 of Ctenodus serratus, from the Coal Measures of Ohio, more nearly 

 than other described species of Dipterus. 



Family COCCOSTEIDAE Smith Woodward. 



Genus DINICHTHYS Newberry. 



Among the mteresting remains of tliis genus contained in the 

 United States National Museum collection may be mentioned the 

 type mandible (Cat. No. 65) upon which the species D. newherryi 

 Clarke was founded, from the Genesee shale of Bristol, New York. 

 Another figured specimen is part of the head-shield of D. pustulosus 

 Eastman (Cat. No. 19) from the Hamilton limestone of Milwaukee, 

 Wisconsin. Indications of the same species in the Upper Devonian 

 State Quarry beds of Johnson County, Iowa, have recently been dis- 

 covered by Prof. Abram O. Thomas, of Iowa State University. Par- 

 ticularly noteworthy among the specimens obtained by him is a por- 

 tion of the dorsomedian shield showing the posterior carinal process. 

 It is shown in plate 8, fig. 8. The corresponding element of a closely 

 related species from the Upper Devonian of Louisiana, Missouri, has 

 recently been described under the name of D. missouriensis by E. B- 

 Branson.* Some fragmentary Dmichthyid plates from the same 

 locahty are preserved in the Museum collection. 



The older restorations of Dinichthys and allied European coccos- 

 tean genera are well known. Within recent years several writers 

 have proposed certain modifications of the earher arrangements of 

 cranial and body plates in typical genera, not aU of which can 

 be said to be entirely successful. The latest attempted recon- 

 struction of DinicUhys terrelli is that of E. B. Branson, pub- 

 lished m the Ohio Naturalist for June, 1908,^ which drew forth 

 some critical comment by Bashford Dean in Science three years later 

 (vol. 34, p. 801). The typical species of Coccosteus, and also that 

 commonly referred to " Bracliydirus" under von Koenen's term of B. 

 hidorsatus, were made the subject of new reconstructions by G. 



» Branson, Et B. The Devonian fishes of Missouri. Bull. Univ. Missouri, vol. 15, 1914, No. 31, p. 61, pi. 

 2, fig. 4. 

 2 Vol. 8, pp. 363-369. 



