3 68 
The Ohio Naturalist, 
[Vol. VIII, No. 8, 
tinguished from the outer by heavier shading. The part that 
projects forward beneath the suborbital is missing in all speci¬ 
mens at the writer’s disposal and is restored in the drawings 
after Newberry 1 and Hussakof. 2 A part of the upper end is 
restored in their specimen but is present in this one. In the 
specimen under consideration there is no indication of a thick¬ 
ened edge of the mandibular support. 
The arrangement of the supero-gnathals as near as can be 
ascertained is the same as in Dinichthys curtus as figured by 
Hussakof. 3 Their exact relation to the suborbital is not clear, 
though it is essentially that shown in figure 1. The anterior 
end of the suborbital is complete on the left side but the postero- 
supero-gnathal is missing. The anterior end of the suborbital 
is missing from the right side. The notch in the anterior end 
of the suborbital apparently fitted against some part of the 
antero-supero-gnathal, but it is impossible to determine this fit 
with the specimens at the writer’s disposal. 
Placing the mandible in its natural relation to the supero- 
gnathals it is found that the posterior end rests just beneath 
the postero-infero-corner of the suborbital and against the inner 
anterior projection of the clavicular. The conclusion that the 
mandible rested against this projection is necessary. There is 
no other bone which could furnish support for it. Hussakof 
indicates this attachment in a general way in figure 1 of the paper 
above cited. 
The slime canal on the marginal does not extend to the angle 
of the marginal but branches to right and left as shown in figure 
2. In other respects the canals do not differ materially from the 
way they are represented by Hussakof in figure 24C of the paper 
just cited. The shape of the skull differs considerably frcm 
Hussakof’s restoration but agrees with Newberry’s figures in 
Plate IV, Monograph XVI, of the United States Geological 
Survey. 
The dimensions of the bones following Hussakof’s method 
of measuring, are as follows: 
1. Monograph XVI, U. S. Geol. Surv., Plate XLVIII, figs. 1 and 2. 
2. Mem. Am. Mus. Nat. Hist., Vol. IX, Pt. Ill, p. 133, fig. 19. 
3. Mem. Am. Mus. Nat. Hist., Vol. IX, Pt. Ill, p. 112, fig. 5. 
