HOLLAND: THE OSTEOLOGY OF DIPLODOCUS MARSH 241 
are formed behind, at the extreme upper inner margin, by the outer surface of the 
parietals for a short distance. The remainder of the posterior wall is formed by the 
forward surfaces of the exoccipitals and the squamosals. ‘The anterior wall is formed 
at the extreme inner margin by the parietals, and the remainder of the anterior wall 
,e 
Linea 
ft 
\\ 
Mf 
SW 
y 
tt 
\\ 
x 
Fic. 10. Inferior view of posterior part of skull of Diplodocus (No. 552, Car. Mus. Cat. Vert. Fossils, one half nat- 
ural size). 0.C., occipital condyle; BO., basioccipital ; P.OC., paroccipital processes of exoccipitals ; HXO., exoccipi- 
tals ; SQ., squamosals ; BS., basisphenoid ; 4S., superior wing of alisphenoid ; a/sp., inferior wing of alisphenoid ; P.O., 
postorbitals ; /'&., frontals; O S., orbitosphenoids; P.S., presphenoid or rostral portion of basisphenoid ; P.F., pre- 
frontal ; S.G., stapedial grooves ; P.C A., foramen for posterior carotid artery ; F.0., fenestra ovalis ; 1X., glossopharyn- 
geal foramen ; XJI., hypoglossal foramen ; 6.0.p., basioccipital processes ; b.pt., basipterygoid processes; 1, median 
eustachian foramen ; 2, posttemporal fossze ; 3, supratemporal fossze. 
is formed by the posterior external surfaces of the postfrontals, the postorbitals, and 
the alisphenoid where the latter articulates between the postfrontal and the exoc- 
cipital. The internal surface of the upper end of the quadrate appears to form a 
small part of the inner margin of the supratemporal fossa above, but below enters 
into it to a larger extent. 
The Infratemporal Fosse (Fig. 3 and Plates XXIII. and XXVI.).— The infra- 
temporal fossa is bounded above by the postorbital and the jugal, below by the 
quadrate and the’ quadratojugal. 
