598 



PISCES. 



[GIS. HAR. 



like Peltodus, but distinguished by the 

 cleft condition of the crest. Type F. 

 bifidus. 



bifidus, St. John & Worthen, 1875, Geo. 

 Sur. 111., vol. 6, p. 414, 

 Kaskaskia Gr. 

 tricuspidatus, St. John & 

 Worthen, 1875, Geo. Sur. 

 111., vol 6, p. 415, Kaskas- 

 kia Gr. 



fldus. GAMPSACANTHUS, St. John & 



Worthen, 1875, Geo. Sur. 111., vol. 6, p. 

 471. [Ety. gampsos, curved; akantha, 

 spine.] Spines long, laterally com- 

 pressed, tapering, costate, with larger 

 and smaller tubercles ; posterior margin 

 denticulate ; base expanded ; pulp cav- 

 ity large. Type G. typus. 



FIG. 1131. Fls- 

 t o d u s b i- 



FIG. 1132. Gampsacauthus typus. Side view of a 

 spine magnified 2 diam., aud transverse sec- 



latus, St. John & Worthen, 1875, Geo. 

 Sur. 111., vol. 6, p. 474, Keokuk Gr. 



squamosus, St. John & Worthen, 1875, 

 Geo. Sur. 111., vol. 6, p. 473, St. Louis Gr. 



typus, St. John & Worthen, 1875, Geo. 



Sur. 111., vol. 6, p. 472, St. Louis Gr. 

 GISACANTIIUS, St. John & Worthen, 1875, 

 Geo. Sur. 111., vol. 6, p. 440. [Ety. 

 geison, a border; akantha, a spine] 

 Spine curved posteriorly, anterior angle 

 a simple raised keel ; lateral faces bear- 

 ing longitudinal rows of tubercles; pos- 

 - terior face longitudinally keeled. Type 

 G. stellatus. 



bullatus, St. John & Worthen, 1875, Geo. 

 Sur. 111., vol. 6, p. 441, Kaskaskia Gr. 



stellatus, St. John & Worthen, 1875, Geo. 

 Sur. 111., vol. 6, p. 440, St. Louis Gr. 



Fio. 1133. Glymmatacan thus Irish!. Fragment 

 of npiue. 



GLYMMATACANTHUS, St. John & Worthen, 

 1875, Geo. Sur. 111., vol. 6, p. 446. [Ety. 

 glymmatos, engraved ; akanlha, spine.] 

 Fin ray vertically elongated, posteriorly 

 arched, laterally compressed; lateral 

 faces covered with stellate or striated 

 tubercles. Type G. irishi. 



irishi, St. John & Worthen, 1875, Geo. 

 Sur. 111., vol. 6, p. 447, Kinderhook or 

 Waverly Gr. 



petrodoides, St. John & Worthen, 1883, 

 Geo. Sur. 111., vol. 7, p. 250, Kaskas- 

 kia Gr. 

 rudis, St. John & Worthen, 1883, Geo. 



Sur. 111., vol. 7, p. 249, Keokuk Gr. 

 GLYPTOLEPIS, Agassiz, 1836, Poiss. Foss., 

 vol. 2, p. 179. [Ety. glyptos, sculptured ; 

 lepis, scale.] Fins long, sometimes pen- 

 dulous; anterior dorsal opposite ven- 

 tral, and posterior dorsal opposite anal ; 

 tail fin long, spreading below ; shoulder 

 bones huge ; teeth minute ; scales of 

 great size in proportion to the animal, 

 and deeply sculptured. Type G. el- 

 egans. 

 microlepidotus, Agassiz, 1836, Poles. 



Foss., vol. 2, p. 179, Devonian, 

 quebecensis, Whiteaves, 1889, Trans. 

 Roy. Soc. Can., vol. 6, p. 77, Low. 

 Devonian. 



GNATITORHIZA, Cope, 1883, Proc. Am. 

 Phil. Soc., vol. 20, p. 629. [Ety. 

 gnathos, jaw ; rhiza, root.] Founded 

 upon some ganoine teeth. The def- 

 inition is too meager for identifica- 

 tion, and the genus may never again 

 be recognized. Type G. serrata. 

 eerrata, Cope, 1883, Proc. Am. Phil. 



Soc., vol. 20, p. 629, Permian. 

 GYRACANTHUS, Agassiz, 1833, Recherches 

 sur les Poisspns Fossiles, t. 1, p. 87. 

 [Etj\ gyros, a circle ; akan- 

 tha, spine.] Fin spines 

 very large, gradually ta- 

 pering to the apex, and 

 slightly arched back- 

 ward; inserted base 

 small, rapidly tapering ; 

 posterior margin feebly 

 armed with two rows of 

 small denticles; surface 

 of the sides covered with 

 very oblique ridges, which 

 meet at an angle on the 

 anterior face. Type G. 

 formosus. 



all en i, Newberry, 1873, 

 Ohio Pal., vol. 1, p. 331, 

 Cuyahoga shale, 

 compressus, Newberry, 

 1873, Ohio Pal., vol. 1, p. 

 230, Cuyahoga shale, 

 cordatus, St. John & Wor- 

 then, 1883, Geo. Sur. 111., 

 vol.7, p. 251, Keokuk Gr. 

 duplicatus, Dawson, 1868, 

 Acad. Geol., p. 210, Coal 

 Meas. 



magnificus, Dawson, 1868, 

 Acad. Geol., p. 210, Sub- 

 carboniferous. FIG. 1134. Gy- 

 HARPACODUS, Agaesiz, 1869, racautiuis ai- 

 Catal. Foss. Fish, Collec- ^ e ; Anterior 

 tion of Earl of Enniskil- 

 len, and St. John & Worthen, in Geo. 

 Sur. 111., vol. 6, p. 354. [Ety. harpe, a 



