170 WOODWARD : FOSSIL FISHES OF THE UPPER LIAS OF WHITBY. 
Fig. Page. 
2. Pachycormus aeutirostris, Agassiz ; head, left lateral 
aspect, ag., angular ; c.o., circumorbitals ; d., den- 
tary ; mx., maxilla ; s.o. (1 and 2)., suborbitals ; scl, 
sclerotic. [P. 3705a.] .. ... ... 165 
2a. Gular plate of same specimem. ... ... ... 166 
3. Pachycormus acutirostris, Agassiz ; jaws of left side. 
d., dentary; 7nx., maxilla; 
s.mx., supramaxilla. [P. 
37056.] ... ... 168 
4. „ left opercular apparatus, hr., 
branchiostegal rays ; op., 
operculum ; p.op , preoper- 
culum ; s.o/?.,suboperculum. 
[P. 884^>.] .. ... 167 
Note. — All the specimens represented on Plates xx. and xxi. 
are preserved in the British Museum, and the numbers in square 
brackets refer to the Register of the Department of Geology. Unless 
otherwise stated, the figures are of the natural size. 
