The ventral armature of the body is rather weak as compared to that of Sauropleura pauciradiatus, but it is still composed of closely packed scutes arranged en chevron. The character of the ventral armature and the sculpturing of the interclavicle are taken as the principal specific characters. From the other species of the genus the present form differs in its more slender elements of the ventral armor and in the form of the skull. The ribs are not clearly defined.

Measurements.

mm.
Median length of skull 70
Posterior width of skull 40
Anterior width of skull 20
Length of jaw 50
Anterior width of jaw 7
Posterior width of jaw 12
Length of mandibular tooth 1.5
Length of entire specimen150
Width across belly, maximum 47
Length of interclavicle 27
Width of interclavicle 13
Width across posterior extension 4

Sauropleura digitata Cope.

Cope, Proc. Phila. Acad. Nat. Sci., p. 216, 1868.

Cope, Trans. Am. Phil. Soc., XIV, p. 15, 1869.

Cope, Geol. Surv. Ohio, II, pt. II, p. 403, pl. xxxvii, fig. 1, 1875.

Type: Specimen No. 8004 G, American Museum of Natural History.

Horizon and locality: Linton, Ohio, Coal Measures. ([Plate 20, fig. 4.])

This species is represented by a single individual which is quite distinct from other members of the genus. The specimen has been spread over a surface of the coal, and exhibits ventral armature, dorsal region with ribs, and anterior and posterior limbs. Skull and caudal region not present.

The ventral armature is arranged in parallel lines directed obliquely forwards and continuous on the median line, forming there a chevron. The individual elements are oat-shaped, and acuminate at both ends. They are moderately imbricate in an antero-posterior section. On the pectoral region between the fore limbs the series of scutellæ assume different directions, forming chevrons directed backwards, and forming with those of the belly a complete X.