PYG. RHY.] 



PISCES. 



611 



Pygopterus, Agassi z, 1833, Poiss. Foss., t.,1. 

 p. 10. [Ety. pyge, rump ; pteron, fin.] 

 Body large, elongate, ovate ; fins large, 



FIG. 1170. Ptyctodus calceolus. Side view. 



with fulcral scales ; anal fin long, nearly 

 opposite dorsal ; ventrals small ; pecto- 

 rals small, falcate ; caudal large, notched; 

 upper jaw longer than the lower; endo- 

 skeleton strong; scales small, rhom- 

 bpidal. Type P. humboldti. Not defi- 

 nitely known from America. 

 scutellatus, Newberry, 1857, Proc. Acad. 

 Nat. Sci., vol. 8, p. 98, Coal Meas. Too 

 poorly defined to warrant recognition. 



FIG. 1171. Pygopteris mandibularis. Outside and 

 under surface of scale maguined. 



RHADINICHTHYS, Traquair, 1877, Quar. Jour. 

 Geo. Soc. Lond., vol. 33, p. 548. [Ety. 

 rhadinos, slender; ichthys, fish.] Body 

 slender ; jaws with a row of incurved 

 laniaries, outside of which there are 

 smaller teeth ; principal rays of pectoral 

 fin as in Pygopterus; dorsal far back, 

 nearly opposite the anal. Type R. 

 ornatissiinus. 



FIG. 1172. Rhadinichthys alberti. 



alberti, Jackson, 1851, (Palseoniscus al- 

 berti,) Rep. on the Albert Coal-mine, 

 New Brunswick, Coal Meas. 



cairnsi, Jackson, 1851, (Palseoniscus 

 cairnsi,) Rep. on Albert Coal-mine, 

 New Brunswick, Coal Meas. 



modulus, Dawson, 1877, (Palseoniscus 

 modulus,) Can. Nat. and Quar. Jour. 

 Sci., vol. 8, Carboniferous. 

 RHIZODUS, Owen, 1840, Odontography. 

 [Ety. rhiza, a root; odous, tooth.] Jaws 

 massive, bearing large, compressed, 

 double-edged teeth, with sulcated bases 



in each dental bone, and numerous 

 smaller ones ; scales large, rotundato- 

 quadrate, thin, inner surface concentric- 

 ally lined; outer 

 surface tubercu- 

 late. Type R. hib- 

 berti. 



angustus, Newberry, 

 1857, Proc. Acad. 

 Nat. Sci. Phil., vol. 

 8, p. 99, Coal Meas. 

 Poorly defined, 

 hardingi, Dawson, 

 1868, Acad. Geol., 

 p. 254, Subcarbon- 

 iferous. 



incurvus, Newberry, 1857, Proc. Acad. 

 Nat. Sci., vol. 8, p. 99, Coal Meas. 

 Poorly defined. 



FIG. 1173. Rhizodus occidentals. Scale. 



lancifer, Newberry, 1857, Proc. Acad. Nat. 

 Sci. Phil., vol. 8, p. 99, and Ohio Pal., 

 vol. 1, p. 342, Coal Meas. 

 occidentalis, Newberry & Worthen, 1866, 

 Geo. Sur. 111., vol. 2, p. 19, Coal Meas. 

 quadratus, Newberry, 1873, Ohio Pal., 

 vol. 1, p. 343. Coal Meas. 



reticulatus, Newberry & 

 Worthen, 1870, Geo. Sur. 

 111., vol. 4, p. 349, Coal 

 Meas. 



RHYNCHODUS, Newberry, 1873, 

 Ohio Pal., vol. 1, p. 307. 

 [Ety. rhynchos, beak ; odous, 

 tooth.] Teeth somewhat 

 half-circular, compressed, 

 exterior margins curved ; 

 one cornua produced, the 

 other obtuse ; straight side the triturat- 

 ing or cutting edge. Type R. secans. 



FIG. 1174. Rhynchodus frangens. 



crassus, Newberry, 1873, Ohio Pal., vol. 

 1, p. 312, Up. Held. Gr. 



