HOLLAND: THE OSTEOLOGY OF DIPLODOCUS MARSH ; 235 
tion of the maxillary which borders the nasal opening; below they articulate 
with the superior process of the jugal, and along their posterior margin with the 
yi | 
Ii, i} 
Wit) y 
rh 
9 lif)! 
if 
Wee 
Lye a 
Fig. 7. Supra- 
orbital. Sketch 
of the outline of 
the bone as 
shown in Marsh’s 
type specimen 
Fic. 6. Superior view of posterior portion of skull of Diplodocus , No. “7, Car. Mus. (U.S. N. M., No. 
Cat. Vert. Fossils, one half natural size). 0O.C., occipital condyle ; LX0O., exoccipitals ; 2673). The upper 
P.OC., paroccipital processes of exoccipitals ; SQ., squamosals ; S.O., supraoccipital ; PA., end is broken off 
parietals; F., frontals; PF., prefrontals; PO.F., postfrontals; P.O., postorbitals ; A.S., in this specimen. 
alisphenoids; 1, foramen magnum ; 2, posttemporal fosse ; 3, supratemporal fosse; 4, (One half natural 
median anterior processes of the frontals ; 5, lateral anterior processes of frontals. size. ) 
lachrymals. They might on account of their location be well styled preorbitals. 
In the specimen (U7S. N. M., No 545), the bone is shown dislodged from its place 
and bent back across the matrix which fills the upper part of the orbital cavity. In 
the specimen (ES. N. M., No. 969), the bone is represented by some fragments (see 
Plate XXVI.), and in the specimen (U.S. N. M., No. 2672), it is shown just behind 
the antorbital vacuity. (See Plate X XIII.) 
The Lachrymals (Fig. 3). —The lachrymals are thin plates of bone articulating 
along the lower posterior margin of the supraorbitals and forming a portion of the 
lower anterior wall of the orbital cavity. The bone is found in situ in the type 
specimen of Professor Marsh (U. 8. N. M., No. 2673). (See Plate XXIII.) It does 
not appear to exist in the specimen in New York (U=S-N- M., No. 969). 
The Basisphenoid (Figs. 5, 8, and 10).—The basisphenoid articulates posteriorly 
with the basioccipital and the exoccipitals and laterally with the alisphenoids and 
