AND MES0Z(3IC FISPIES. 
447 
COELODUS Heckel. 
OoELODUS isRowxii sp. iiov. Plate XX, Fig. 10. 
Represented by a iiart of the left mandibular ramus which supports the bases 
of five teeth in anteroposterior line. Two rows, are distinct!}^ represented, and a third 
internal row is represented bj^ the extremities of the bases of the teeth only. 
The distinctive character of the species is seen in great transverse extent of 
the teeth of the middle row, and the depressed ledge of the jaw just external to the 
smaller external row. The teeth of the middle row are narrow anteroposteriorly, the 
long diameter being about two and a half times the anteroposterior. They are in- 
clined slightly backward externally. The crowns of the teeth of the external row 
are not over half the transverse diameter of those of the second, while of similar 
anteroposterior diameter. They are directed more obliquely backward than those 
of the second row, and they stand on a convex ridge of the bone, so that their 
grinding faces project beyond those of the second row. All tire teeth are in con- 
tact. The only crown preserved is rveathered ; it does not display a median de- 
pression. 
A single separate crown found near the present specimen, may belong to the 
same species. It is elongate, transverselj^ gently arched, and its surface is without 
depression or sculpture. 
Measurements. 
MM. 
Anteroposterior extent of five teeth of external row ; 24 
Diameters of tooth of second row I ^ 
(transverse; 14 
Diameters of tooth of third row I , 5 
( transverse ; i 
From the same locality and horizon as the two species above de.scribed. The 
specimen on which C. brownii is founded was discovered by Prof. A. P. Brown, 
to whom I dedicate it with much pleasure. 
EXPLANATION OF PLATES. 
Plate XVIII. 
Fig. 1-5. Symmoriiim renifor7ne Cope, part of specimen de.scribed on pages 
428-32, one-fourth natural size. Lettering: Sc, Scapulocoracoid ; P, Metapterygium ; 
Eb, epibranchials ; s, skull ; j, jaw. 
Figs. 2—3. Symmorium reniforme Cope, mandibular teeth, natural size ; 2—3 
from front ; 2a, from below ; 2b, from above ; 2c, lateral denticles, enlarged. 
Figs. 4-5. Branchial teeth, much enlarged. 
Fig. 6. Orodus basalis Cope, head and part of body, two-third.s natural size. 
Fig. 7. Cope, tooth, internal side ; rt, external side ; h. section. 
S 2 iecimens in collection of F. IL Jelliflfe. 
