Cretac. Vert., p. 189 et seq.
"Teeth subcylindric, without serrate or cutting edges, occupying the maxillary, premaxillary, and dentary bones; size, irregular; premaxillary, median maxillary, and dentary much reduced. No foramina on inner face of jaws. Teeth on the premaxillary reduced in number. Opercular and pre-opercular bones very thin. Cranial bones not sculptured."
Portheus thaumas (?), Cope.
Loc. cit. p. 196.
Maxillary large, teeth three; third mandibular small, without cross groove in front of it.
A single tooth from the cretaceous sandstone of Cement Gulch, Col., is provisionally referred to this species; the reference cannot be certain, as the specimens described and figured by Professor Cope have the crowns of the teeth broken. The tooth is not so long as the largest tooth of P. molossus, but is of proportionately greater diameter and not so straight. It is conical and recurved, and shows two very obscure cutting-edges, which divide the crown into two unequal faces. It has faint longitudinal striations on all sides, and the apex is sharp.
Measurements.
| M. | |
| Fore-and-aft diameter at the base | 0·613 |
| Height of crown | 0·020 |
NEMATOGNATHI.
SILURIDÆ.