EASTMAN : CARBONIFEROUS FISHES FROM THE CENTRAL WEST. 183 



except that the coronal surface is not roughened or vermiculated. The latter 

 appearance may be perhaps attributed to varying conditions of weaff and pres- 

 ervation, and is doubtfully of specific value. 



PHYSONEMUS Agassiz. 



The mostly small, highly tuberculated Ichthyodorulites known as Physone- 

 mus, Erisraacanthus, Gampsacanthus, Dipriacanthus, etc., interpreted as lat- 

 eral head-spines, may be provisionally referred to the Cochliodontidae. 



Physonemus asper, nom. nov. 



1859. Xystracanthus arcuatus J. Leidy, Proc. Acad. Nat. Sci. Philad., p. 3. 



1873. Xystracanthus aratatus J. Leidy, Kept. U. S. Geol. Surv. Territ., Vol. I., 



p. 312, PI. XVIL, Fig. 25. 

 1875. Xystracanthus arcuatus St. John and "Worthen, Pal. Illinois, Vol. VI., p. 457. 



The type species of Physonemus having been named P. arcuatus by M'Coy 

 in 1848, it becomes necessary to designate the type of Leidy's so-called 

 " Xystracanthus " by a new specific title on removing it to Physonemus. 

 The name P. asper is accordingly proposed for it in allusion to the coarsely 

 tuberculated style of its ornamentation. Jaekel's theoretical association of 

 spines of this character with the teeth of Petalodus and Polyrhizodus, and also 

 with the dermal tubercles of Petrodus, has not been proved by any direct 

 evidence, and militates with the facts of distribution. 



Formation and Locality. — Missourian ; Leavenworth, Kansas. 



CESTRAGIONTIDAE. 



ORODUS Agassiz. 

 Orodus intermedius, sp. nov. 



(Plate 4, Figs. 35, 36.) 



Type. — Detached tooth ; Museum of Comparative Zoology. 



Teeth of medium size, upwards of 3 cm. in length. Coronal contour grad- 

 ually rising into a nearly smooth dome-shaped median eminence ; longitudinal 

 crest low, slightly wavy, giving off several groups of branching transverse 

 wrinkles extending on either side, and forming .slight buttresses on the outer 

 coronal margin ; base of crown faintly crenulated along the inner margin. 



The unique tooth answering to the above description was obtained by the 

 late Mr. Samuel A. Miller from the Upper Coal Measures on the opposite side 



