366 
The Ohio Naturalist. 
[Vol. VIII, No. 8, 
The relations of the dorsal to the dorso-laterals is shown in 
both restorations. In the specimen the postero-dorso-lateral 
and antero-dorso-lateral are firmly united in their original rela¬ 
tion. Some fragments are missing from the upper margin and 
are restored in outline in the drawings. The right margin of the 
dorso-median is missing in the specimen but its position and shape 
are almost perfectly indicated on the dorso-laterals. Outside of 
the dotted line in figure 2 the antero-dorso-lateral is restored. 
As the left postero-dorso-lateral is crushed down on the right 
dorso-laterals their relation to one another is obscured. The 
writer is not satisfied with the outline of the antero-dorso-lateral 
as it is shown in the drawing, but the bones are undoubtedly in 
their natural association and the antero-dorso-lateral is the only 
bone to fill the space in front of the posterior bone. The over¬ 
lapping part of the antero-dorso-lateral is very thin. 
The relation of the antero-dorso-lateral to the skull is deter¬ 
mined beyond controversy by the specimen under discussion and 
by two other specimens in the Museum of Oberlin College. The 
relation is determined by placing the dorso-median and dorso- 
laterals in association and placing the median line of the dorso- 
median in the median line of the skull and the articulating part 
of the antero-dorso-lateral in its socket. The anterior edge out¬ 
side of the articulation overlaps the depressed edge of the poster¬ 
ior part of the skull for about two centimeters. A specimen of 
Dinichthys intermedins shows the same relation, and in a speci¬ 
men of Dinichthys recently collected from the Huron shale in 
which both antero-dorso-laterals are preserved in their natural 
relation to the skull the same relation is shown. 
The position of the clavicular and its relations to other bones 
is definitely shown and is represented in both restorations. 
The main articulation is with the depression in the antero-dorso- 
lateral. Its anterior edge overlaps for more than two centimeters 
the depressed posterior edge of the skull though it does not arti¬ 
culate with the skull. The posterior end of the suborbital rests 
against a large part of the anterior edge of the clavicular between 
its two anterior projections. The outer of the anterior projections 
which just reaches the lower edge of the suborbital probably 
supported a lateral appendage. It diverges from the inner projec¬ 
tion at an angle of about forty degrees but soon curves inward and 
runs nearly parallel with the inner part. The distal end of this 
projection is a separate bone. It is sometimes ankylosed with 
the rest of the bone but is detached in many cases. It should be 
classed as a distinct skeletal element. If it is homologous with 
any bone of other vertebrates the writer is in doubt about the 
homology. The inner anterior projection of the clavicular ex¬ 
tends further forward than the outer, and the anterior end sup¬ 
ports the mandible. In the restorations the inner part is dis- 
