606 



PISCES. 



[PET. 



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. 

 PBTALORHYNCHUS, 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, 

 Geo. Sur. 111., vol. 6, p. 406, St. Louis Gr. 



pseudosagittatum, St. John & Worthen, 

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

 Louis Gr. 



spatulatum, St. John & Worthen, 1875, 

 Geo. Sur. 111., vol. 6, p. 408, St. Louis Gr. 



striatum, Newberry & Worthen, 1866, 

 Geo. Snr. 111., 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. patelliformis. 



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. 



PHANEROPLECRON, 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. 



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

 Sur. 111., 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 



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. Fl Q- 1158. Phce- 

 Type P. sophite. bodus sophiee. 



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



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

 PHYSONEMUS, Agaasiz, 1843, Recherches sur 

 les Poissons Fossiles,t. 3, p. 176. [Ety. 

 physa, bladder ; nema, 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 & Worthen, 1875, 

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

 Louis Gr. 



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

 Sur. 111., vol. 7, p. 252, St. Louis Gr. 



gigas, Newberry & Worthen, 1870, Geo. 

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

 ton Gr. 



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

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



FIG. 1159. Platyodns liiieatns. 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; odout, 

 tooth.] Teeth elliptical in outline; 

 crown arched in both directions ; sur- 



