68 THE WASATCH A^TD BRIDGER FAUNJ3. 



in the caudal fin. (Psuedobranchite and pyloric appendages). Clupeid<B. 

 Tail, homocercal; pterotic, normal; basis cranii, simple; basal branchihyals 

 and superior pharyngeals, each three ; (no pseudobranchige) Osteoglossida. 

 To the first named family belongs the genus Diplomystus; to the last 

 named, Dapedoglossiis. 



DAPEDOGLOSSUS Cope. 



Bulletin U. S. Geol. Snrv. Terra., 1877, p. 807 (Augost 15). Phareodua (nomen nudum) Lcidy. Proceed. 

 Acad. Nat. Sci. Phila., 1873, p. 99. Fiual Report U. S. Geol. Snrv. Terra., i, p. 193. 



A single row of elongate acute teeth on the premaxillary, maxillary, 

 and dentary bones, vomer, tongue, and (?) basihyal bones closely studded 

 with short conic grinding teeth. Mouth rather short. Pectoral fin with 

 the anterior ray elongated ; dorsal fin not elongate, with the anal well 

 separated from the caudal. No beards. Two vertebrae included witliin the 

 caudal fin. 



This interesting genus presents the characters of the family to which I 

 refer it, in its segmented scales, posterior dorsal fin, etc., and does not differ 

 widely in essentials from Osteoglossum. The principal differences between 

 the two genera are, the small mouth in Bapedoglossus, the absence of 

 barbels, and the generally abreviated form. From Arapama, it differs in 

 proportions, and in the abundance of teeth on the bones of the roof and 

 floor of the mouth. 



The peculiar structure of the scales characteristic of this family is well 

 displayed in this genus. The whole of the scale is composed, between the 

 inferior and superior surface layers, of subhexagonal or diamond-shaped 

 cells, which are arranged in spirals trending to the center. Their contents 

 are more thoroughly calcified on the exposed than in the concealed portion 

 of the scale. No radial grooves. Tube of the lateral line issuing by a 

 round pore. 



The discovery of this genus, in the Green River shales, is one of the 

 most interesting in the history of this department of paleontology which 

 has been made. 



Osteoglossum is known only in a recent state, and with a range of dis- 

 b'ibutlon quite unparalleled among Teleostean fishes. Thus one species — 

 0. bicirrhosum, Vand., occurs in Brazil; 0. fonnosum, Schl. Miill., in Bor- 



