COCCOSTEIDiE. 
279 
anterior lateral borders being notched by the orbits (o.) and the 
front border somewhat rounded. A large quadrangular median 
occipital element ( m.o .), and a flanking pair of triangular exocci- 
pitals ( e.o .) form the posterior and the greater part of the postero¬ 
lateral borders; the median occipital tapering anteriorly somewhat 
Pig. 42. 
71. e. 7L. 
Outline of cranial and dorsal shield of Coccosteus decipiens, Ag., restored by 
K. H. Traquair.— a.d.l., anterior dorso-lateral; a.l., anterior lateral; c., cen¬ 
tral; e., ethmoid; e.o., external occipital; m., marginal -;m.d., median dorsal; 
m.o., median occipital; mx., maxillo-suborbital; n., narial opening; o., orbit; 
p., pineal; p.d.l., posterior dorso-lateral; p.l., posterior lateral; p.mx,, pre¬ 
maxilla; jo.o., pre-orbital; pt.o., post-orbital; x., operculum(?). 
less than the exoccipitals. Immediately in front of these plates is 
a pair of central elements (c.) meeting in a wavy longitudinal suture 
at the mesial line ; while the lateral angles of the shield are formed 
by a small pair of quadrangular marginals (m.), wedged in on each 
side between the exoccipital, central, and postorbital ( pt.o .) plates. 
The last-named element is almost as small as the marginal, and 
extends partly into the upper border of the orbital notch, A pair 
of large preorbital plates (p.o.) adjoins the front margin of the 
centrals and postorbitals, forming the anterior two thirds of the 
orbital notch with the antorbital process. These plates meet in the 
middle line of the shield only for a short space in their hinder half, 
