606 



PISCES. 



[PET. — PI,A. 



linguifer, Newberry & Worthen, 1856, 

 Geo.Sur. 111., vol. 2, p. 37, KaskaskiaGr. 



proximus, St. John & Worthen, 1875, 

 Geo. Sur. 111., vol. 6, p. 395, Coal Meas. 

 Petalorhynchus, Agassiz, 1855, in British 

 Pal. Rocks. [Ety. petalos, spread out ; 

 rhynchos, a beak.] Teeth small, crown 

 compressed, thin, concavo-convex, 

 petal-shaped ; higher and narrower 

 than Petalodus; imbricating folds on 

 posterior face forming a short trans- 

 verse band, not extending to the lat- 

 eral angles of the crown; root long, un- 

 divided. Type P. sagittatum. 



distortum, St. John & Worthen, 1875, 

 I no. Sur. 111., vol. 6, p. 406, St. Louis Gr. 



pseudosagittatum, St. John it Worthen, 

 1875, Geo. Sur. 111., vol. 6, p. 405, St. 

 Louis Gr. 



spatulatum, St. John A: Worthen, L875, 

 Geo. Sur. 111., vol.6, p. 408, St. Louis (Jr. 



striatum, Newberry & Worthen, L866, 

 Geo. Sur. III., vol. 2, p, 40, Burling- 

 ton Gr. 

 Petrodus, McCoy, 1848, Ann. and Mag. Nat. 

 Hist., 2d series, vol 2, p. 132. [Ety. 

 petros, a rock ; odous, a tooth.] Conical ; 

 base round or subtrigonal; apex rudely 

 pointed ; sides radiatingly ridged ; os- 

 seous base wider than the crown. Type 

 P. patelliformi8. 



acutus, Newberry & Worthen, 1866, Geo. 

 Sur. 111., vol. 2, p. 72, Coal Meas. 



occidentalis, Newberry & Worthen, 1866, 

 Geo. Sur. 111., vol. 2, p. 70, Coal Meas. 



pustulosus, Newberry & Worthen, 1870, 

 Geo. Sur. 111., vol. 4, p. 369, Burling- 

 ton Gr. 

 Phaneropleuron, Huxley, 1871, 10th Dec- 

 ade Geo. Sur. of Gt. Britain. [Ety. 

 phaneros, open ; pleuron, side.] 



curtum, Whiteaves, 1881, Am. Jour. Sci. 

 and Arts, 3d ser., vol. 21, p. 495, Upper 

 Devonian. 

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

 Sur. HI., vol. 6, p. 251. [Ety. 

 mythological name ; odous, a 

 tooth.] Teeth small ; base irreg- 

 ularly elliptical, strongly pro- 

 duced in Iront and faintly ex- 

 cavated at the median line ; the 

 antero-inferior angles approxi- 

 mate, and laterally curve to the 

 rounded extremities ; broadly 

 though irregularly rounded be- 

 hind ; the angles in front are 

 occupied by a strong, lateral, 

 pad-like prominence, which is 

 more or less distinctly bilobed 

 and beveled to the deeply 

 excavated inferior surface ; pos- 

 terior margin slightly burled ; 

 postero-superior surface moderately 

 convex, and surmounted by a later- 

 ally elongated, well-defined promi- 

 nence, which is situated nearly mid- 

 way between the base of the crown 

 and the posterior border, to which the 

 surface abruptly slopes, and extending 



-Phce- 

 bodua sophlse. 



laterally nearly half the diameter of the 

 base ; the coronal region consists of 

 three strong cusps, of which the ex- 

 terior pair are largest, strongly diverg- 

 ing and moderately recurved or nearly 

 vertical, antero-posteriorly compressed 

 or suboval in section, apparently with- 

 out distinct cutting edges ; median cone 

 similar in shape, erect, more or less 

 produced in front and 

 continued to the shallow 

 median depression in the 

 border ; a rudimentary 

 denticle between the me- 

 dian and lateral cusps. Pick 1158 

 Type P. sophiee. 



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

 Sur. 111., vol. 6, p. 251, Devonian. 

 1'iivsonkmi s, Agassiz, 1st:',, Reeherrhes sur 

 les Pnissons Fossiles, t. :'>, p. 176. [Ety. 

 physa, bladder; nana, thread.] Dorsal 

 spine strong, laterally compressed, 

 deeply imbeded, curved; apex directed 

 toward the front; lateral faces bearing 

 costse and tubercles; pulp cavity large ; 

 base notched. Type P. subteres. 



altonensis, St. John it Worthen, 1875, 

 Geo. Sur. 111., vol. 6, p. 454, St. 

 Louis Gr. 



carinatus, St. John it Worthen, 1875, Geo. 

 Sur. 111., vol. 6, p. 452, Waverly or Kin- 

 derhook Gr. 



chesterensis, St. John & Worthen, 1875, 

 Geo. Sur. 111., vol. 6, p. 455, Kaskas- 

 kia Gr. 



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

 Sur. 111., vol. 6, p. 452, Waverly or Kin- 

 derhook Gr. 



falcatus, St. John it Worthen, 1883, Geo. 

 Sur. 111., vol. 7, p. 252, St. L mis Gr. 



gigas, Newberry it Worthen, 1870, Geo. 

 Sur. 111., vol. 4, p. 373, Burling- 

 ton (ir. 



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

 Sur. 111., vol. 6, p. 453, Keokuk Gr. 



Fig. 1159.— Platyodus lineatns. Crown surface. 



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

 Sur. 111., vol. 6, p. 451, Waverly or 

 Kinderhook Gr. 

 Platyodus, Newberry, 1875, Ohio Pal., vol. 

 2, p. 58. [Ety. platys, broad; odous, 

 tooth.] Teeth elliptical in outline ; 

 crown arched in both directions ; sur- 



