| Measurements of Ptyonius vinchellianus Cope. | |
| mm. | |
| Length of cranium | 20 |
| Width of same | 8 |
| Length of interclavicle | 4-2 |
Cope, Trans. Amer. Phil. Soc., XIV, p. 24, 1869 (Colosteus marshii).
Cope, Geol. Surv. Ohio, II, pt. II, p. 375, pl. xxvii, fig. 6; pl. xxviii, fig. 3, 1875.
Cope, Proc. Am. Phil. Soc., XII, p. 177, 1871.
Type: Specimen No. 1157 G, American Museum of Natural History.
Horizon and locality: Linton, Ohio, Coal Measures.
The head is elongate lanceolate. The upper surface of the frontal bones is punctate-rugose in relief, with short radii toward the margin. The distal two-thirds of the mandible is narrow wedge-shaped; the external surface is coarsely pitted. There are no teeth preserved. The pectoral elements are displaced, but the clavicles are subtriangular, and are strongly ridged toward the inner margin. The interclavicle is short spatulate, the narrow portion directed anteriorly; the posterior rounded. It is coarsely pitted medially, and coarsely and strongly radiate-ridged to the margin. The abdominal armature commences immediately behind the pectoral girdle. It consists of elongate, narrow, subcylindric scales, which meet on the median line, converging anteriorly. Small limbs are present.
| Measurements of Ptyonius marshii Cope. | |
| Type specimen: | mm. |
| Length of fragmentary skull | 7 |
| Width of skull as preserved | 5 |
| Length of entire specimen | 68 |
| Width across pectoral plates | 8 |
| Width across belly | 7 |
| Specimen No. 1098 G, American Museum: | |
| Length of specimen | 32 |
| Width of specimen | 7 |
| 4 scutes of abdominal armature in 1 mm. | |