| Measurements of Third Specimen (No. 4484, U. S. Nat. Mus.). | |
| mm. | |
| Length of specimen | 60 |
| Length of preserved portion of skull | 15 |
| Length of tooth | 25 |
| Posterior width of mandible | 3 |
| Length of anterior Vertebra | 2 |
| Length of rib | 4 |
| Width of rib | 1 |
Genus PHLEGETHONTIA Cope, 1871.
Cope, Proc. Am. Phil. Soc., p. 177, 1871.
Cope, Geol. Surv. Ohio, II, pt. II, p. 366, 1875.
Type: Phlegethontia linearis Cope.
This is one of the most interesting genera of the present series. It rests chiefly on a single specimen of one species, which is not perfect, but which displays the following characters: Head elongate-triangular; body and tail extremely elongate, the dorsal vertebræ without ribs, and the caudals without dilated spines; no ventral armature nor limbs. As a great portion of the length is presented, and no ventral rods or scales are visible, and as this character is confirmed by a second specimen, it probably belongs to the genus. The pectoral shields are also wanting in the specimen, but as there is a considerable vacuity behind the skull of the specimen, it may be that these were lost with other parts. Chevron bones are not observable on the caudal vertebræ. This form is a true amphibian snake.
Phlegethontia linearis Cope.
Cope, Geol. Surv. Ohio, II, pt. II, p. 367, pl. xliii, fig. 2, 1875.
Type: Specimen in the American Museum of Natural History.
Horizon and locality: Linton, Ohio, Coal Measures.