622 



BATRACHIA. 



[ERY. ICH. 



erythrolilicus, see Eryops erythroliticus. 

 ERYOPS, Cope, 1877, Proc. Am. Phil. Soc., 

 vol. 17, p. 188. [Ety. eruo, I protect; 

 ope, view.] Vertebrae rhachitomous 

 throughout ; teeth of external series 

 equal ; some larger ones on the palatine 

 bones; table of cranium produced, 

 bounded by a notch on each side; no 

 horns nor mucous grooves ; pelvic ele- 

 ments co-ossified; no foramen. Type 

 E. megacephalus. 



erytholeticus, Cope, 1878, (Epicordylus 

 erytholeticus,) Proc. Am. Phil. Soc., p. 

 515, Permian. 



ferricolus, Cope, 1878. (Parioxys ferrico- 

 lus,) Proc. Am. Phil, Soc., p. 521, Per- 

 mian. 



megacephalus, Cope, 1877, Proc. Am. Phil. 

 Soc., vol. 17, p. 188, Permian or Triassic. 



platypus, Cope, 1877, (Ichthycanthus 

 platypus,) Proc. Am. Phil. Soc., vol. 17, 

 p. 574, Coal Meas. 



reticulatus, Cope, 1881, Am. Nat., p. 1020, 



Permian. 



EURYTHORAX, Cope, 1875, Ohio Pal., vol. 2, 

 p. 401. [Ety. eurys, broad ; thorax, the 

 breast.] Established on a thoracic shield, 

 having broad, smooth surfaces on the 

 outer borders for the contact of the over- 

 lapping margins of the lateral plates. 

 Subround, with a large excavation from 

 the posterior margin on each side ; nar- 

 rowed portion left in the middle be- 

 hind has a convex outline ; no sculpture. 



Type E. sublsevis. 

 iblsevis, i 



sublsevis, Cope, 1871, Proc. Am. Phil. 

 Soc., p. 177, and Ohio Pal., vol. 2, p. 

 402, Coal Meas. 



PIG. 1185. Hylerpeton dawsoni. Mandible and 

 portion of cranial bone. 



HELODECTKS, Cope, 1880, Pal. Bull. No. 32, 

 p. 11. [Ety. helos, a nail ; dektes, a biter.] 

 Two rows of subround molari- 

 form teeth in each jaw. Type 

 H. paridens. 

 isaaci, Cope, 1880, Pal. Bull. No. 32, 



p. 12, Permian, 

 paridens, Cope, 1880, Pal. Bull. 



"""^No. 32, p. 11, Permian. 



HYLERPETON, Owen, 1862, Quar. Jour. 

 Geo. Soc., vol. 18, p. 5. [Ety. hyle, 

 wood; erpeton, reptile.] Teeth simple, 

 bluntly conical, with large pulp-cavity ; 

 about 13 on one side of a jaw ; two of the 

 anterior ones of the upper jaw twice as 

 large as the others and deeply sunk in 



the jaw. Length of lower jaw J inch ; 

 bones of skull puncto-striate. Type H. 

 dawsoni. 



curtidentatum, Dawson, 1876, Am. Jour. 

 Sci. and Arts, vol. 12, Coal Meas. 



dawsoni, Owen, 1862, Quar. Jour. Geo. 

 Soc., vol. 18, p. 5, and Acadian Geology, 

 p. 380, Coal Meas. 



longidentatum, Dawson, 1876, Am. Jour. 



Sci. and Arts, vol. 12, Coal Meas. 

 HYJ.ONOMUS, Dawson, 1860, Quar. Jour. Geo. 

 Soc., vol. 16, p. 268. [Ety. hyle, wood ; 

 nomos, an abode; forest dweller.] Cra- 

 nial bones thin, smooth ; parietal bones 

 arched ; about 26 teeth in each maxil- 

 lary, elongated, conical, set in a single 

 series, in a furrow, protected externally 

 by an alveolar ridge; teeth longer in 

 intermaxillaries and extremities of man- 

 dibles than elsewhere ; vertebrae ossi- 

 fied, biconcave, with spinous processes ; 

 ribs long and curved ; pelvis large ; 

 ilium long, expanded below, ischium 

 expanded; pubis expanded, triangular 

 where it joins the ischium, round and 

 arched toward the symphysis ; femur 

 thick, nearly straight ; tibia short, stout ; 

 fibula slender; phalanges broad. Der- 

 mal covering of ovate bony scales. 

 Type H. lyelli. 



aciedentatus, Daw- 

 son, 1860, Quar. 

 Jour. Geo. Soc., 

 vol. 16, p. 268, 

 and Acad GPO! FlG - 1186 - Hylonomus 

 Q? Tn I aciedentatus. Maxil- 

 p. d/o, Ooal lary bone magnified; a, 

 Meas. natural size. 



lyelli, Dawson, 



1860, Quar. Jour. Geo. Soc., vol. 16, p. 

 268, and Acad. Geol., p. 370, Coal 

 Meas. 



wymani, Dawson, 1860, Quar. Jour. Geo. 

 Soc., vol. 16, p. 268, and Acad. Geol., p. 

 378, Coal Meas. 



HYPHASMA, Cope, 1875, Proc. Acad. Nat. 

 Sci., p. 16, and Ohio Pal., vol. 2, p. 387. 

 [Ety. hyphasma, a web.] Vertebrae os- 

 seous ; posterior dorsals with fan-like 

 neural spines, ventral armature con- 

 sisting of rhomboidal scuta, forming 

 packed rows arranged in chevrons, di- 

 rected backward, on top of which are 

 the usual rod-like scales arranged in 

 packed chevrons with the angle directed 

 forward. Type H. Isevis. 



FIG. 1187. Hyphasma lv 



Isevis, Cope, 1875, Proc. Acad. Nat. Sci.. 

 p. 16, and Ohio Pal., vol 2, p. 387, Coal 

 Meas. 



ICHTIIYACANTHUS, Cope, 1877, Pal. Bull. No. 

 24, and Proc. Am. Phil. Soc., p. 573. 



