Cope referred to S. scutellata the larger part of an individual with strongly developed ventral scutellation. This he figured on plate XXXVI, fig. 2 ([123]). Even a cursory glance will, however, suffice to show that the sculpturing of the clavicle just described and that exhibited by the specimen there figured are identical. Closer examination shows important differences between the species, the principal distinctions being the strongly developed ventral scutellæ in Sauropleura scutellata, the difference in form and sculpture of the interclavicles, and the posterior extension of the interclavicle in S. scutellata which is wanting in S. pauciradiata. The sculpturing of the interclavicle in the form figured by Cope as S. scutellata, just referred to, is identical with the sculpture of the clavicles, as would be expected. The ridges on all of the pectoral elements of S. pauciradiata are strong and are rather few in number, while in S. scutellata the sculpturing is more in the form of interrupted grooves.

The specimen ([plate 14, fig. 3]) exhibits the great part of the body with one fore limb. The skull is wanting. The belly was very broad and strongly protected by broad, long scutes arranged en chevron. The scutes are close together and form a compact ventral armor for the animal. The fore limb is very weak. The humerus is represented by its distal end only. The radius and ulna are very short and weakly developed in comparison to the size of the animal. The limbs could not have supported the animal on land and served, probably, merely as organs of equilibration, for the animal was undoubtedly aquatic. The fingers are not all preserved and there is no carpus.

Fig. 34.
A. Interclavicle of Sauropleura pauciradiata Cope. × 1. (After Cope.)
B. Left clavicle of Sauropleura pauciradiata Cope. × 1. (After Cope.)

Numerous other remains formerly associated with S. scutellata are here referred to S. pauciradiata, on account of the strongly developed ventral armor, which is different from that of the type of S. scutellata. The remains do not, however, add to our knowledge of the anatomy of the forms, as they are very fragmentary.

Two skulls are provisionally associated with this species. One of these skulls is figured by Cope ([123]) on plate XXXIII, fig. 1. It is there referred to S. scutellata. That it can not, however, be referred to that species is manifest when the teeth are observed. In the type of S. scutellata the teeth are very small, sharp denticles, while in the skull under discussion the teeth are well developed and their bases are longitudinally grooved. The teeth are elongate in the anterior part of the skull and are shorter posteriorly. They are, however, all strong. The skull is acuminate and the orbit is located about midway of its length. The jaw is slightly longer than the cranium. The structure of the cranium can not be determined in either skull, and in one only the position of the orbits and the teeth.

Measurements of the Specimens of Sauropleura pauciradiata Cope.

mm.
Length of clavicle, left 43
Width of clavicle 25
Space between ridges 2
Large specimen No. 8657 G and obverse ([13])
described us Colosteus scutellatus Newb.
mm.
Length of specimen, as preserved117
Width of specimen, maximum 61
Length of forearm 9
Length of hand 10
Length of metacarpus 5
Length of clavicle 4
Width of clavicle 18
Length of interclavicle 40
Width of interclavicle 23
Width of a ventral scute 1.5
Length of scute from angle to end 35
Skull No. 8666 C, plate xxiii, fig. 1 (Cope, 123), Colosteus scutellatus.
mm.
Length of skull, as preserved 65
Width of skull 40
Diameter of orbit 6
Length of mandible 7
Width of mandible, maximum 10
Length of longest tooth 5
Width of tooth at base 1.5
Skull Nos. 8602 G and 8608 G.
mm.
Length of skull, as preserved 50
Width of skull 60
Diameter of orbit 15
Length of mandibular tooth 4.5