190 PROF, OWEN ON A THERIODONT REPTILE 
Tn the thickness of the premaxillary, on the inner side of the 
three middie incisors, were indications of alveoli of successional 
teeth. ‘Those near the third and fourth incisor were subcircular 
spaces filled with the black matrix; that next the second incisor 
contained the apex of a tooth-germ showing a thin investment 
of enamel. It was of a semicircular form, with the base feebly 
undulated and the angles slightly produced. From this I inferred 
that the crown of the tooth, near its apex, was biporcate, the ridges 
being in front and behind, and dividing the outer more convex from 
the inner much less convex sides of the crown. The two diameters 
of this apical section are 10 millims. and 6 millims. The formative 
cavity, which is filled outside the tooth with black matrix, is 13 
millims. by 11 millims. The soft tissues of the tooth-capsule and 
periost originally occupied this space. There was an indication of a 
similar nidus of a successional incisor near the section of the 
foremost tooth, 7 1. 
Another transverse section of a part of the alveolar border of this 
premaxillary which projected beyond the line of the foregoing section, 
crossed the third incisor at or near the base of the crown. It 
showed an indication of the anterior coronal ridge or production of 
the dentine, which, further on in the crown, would have supported 
the beginning of the enamel ridge ; but such support of the opposite 
or posterior ridge had subsided, and the dentine presented there a 
convex outline. The two diameters of the section are 30 millims. 
and 20 millims. No enamel is shown in any of the sections save 
that of the apex of the crown of the successional incisor. From 
this fossil I inferred that I might be on the trace of a Theriodont 
with the upper incisive formula of Gorgonops, viz. 15—5d*, 
A diligent quest and comparison of the other fragmentary repre- 
sentations of what Mr. Bain regarded and reported as “ loose bones 
and fragments of bones of,” I presume, the same ‘large Saurian ” 
led to the recognition of the portion of the left maxillary, the subject 
of fig. 1. It includes the trace of the socket of the canine, s, with 
part of the base or root of that tooth, c, and of its pulp-cayity, p, 
which contained some infiltrated matrix. 
The widest part of what was left of the socket is 35 millims. 
* across; but it does not include all the outer wall; and the transverse 
curve of the retained portion of the tooth indicates a more consider- 
able circumference than is here shown. 
The length of the preserved part of the socket is 43 inches; but 
the outlet, with those of the sockets of the succeeding molars, has 
been broken away. ‘The bases of three of these molars, in what 
remained of their sockets, were obvious, and a section along the rest 
of the alveolar border (fig. 2) brought into view eight others of 
similar shape and size. 
The foremost of the molars (fig.1, m1) appears to have pro- 
truded close to the canine. The fore-and-aft diameter of its preserved 
base is 15 millims.; that of the pulp-cayity is 8 millims. The 
* «Descriptive and Illustrated Catalogue of the Fossil Reptilia of South 
Africa,’ 4to, 1876, p. 27, pl. xxi. fig. 2, 71, 2, 3, 4, 5, 
ee 
