EXPLANATION OF PLATES. 
PLATE IIl. 
Figure 1.—Skull of Diplodocus longus, Marsh; side view. 
Figure 2.—The same skull; front view. 
Figure 3,—The same skull; top view. 
All the figures are one-sixth natural size. 
PLATE IV. 
Figure 1.—Skull and sbrencgrag of Diplodocss longus, ae seen from above, 
one-sixth natural size; aperture in maxillary; 4, antorbital opening; ¢ 
ipsa opening; c’, cere hemis aren; d, orbit; e, lower temporal fossa ; 
f, fro hege cal ft fo nelle; m, ma axill ry bone; m’, ee n, nasal 
mace ie: ol, olfactory lobes; op, optic lobe; p, parietal 
568 ee Of ‘re fontl bone; pm, pre-maxillary bone; 4, caine bone; 4); 
quadrato-jug 
sive meds teeth : — longus, Marsh; side view, one-half 
atural size; e, enamel; 
Figure 3.—Section of cedar ipieidoces longus, Marsh; one-half natural 
size, howe ‘Rosen tooth { (ourth) in position, dad five —— is al teeth 
in dental cayit neo , outer wall; b, inner wall; ¢, cavity; f, fora 
opens 4.-- Twelfth caudal vertebra of Diplodocus longus, Marsh; side view, one- 
sixth State ral eee c, anterior face for chevron ; ce’, posterior ithe for chevron; 
8, neural spine; 2, pre-zygapophysis; 2’ , post-zygapophysis. 
Figure 5.—The same vertebra ; bottom view; size and letters as in Fig. 4. 
Figure 6.—Chevron found poser bo — and oe vertebree of Diplodocus 
longus, Marsh; top and nth natural size; a, anteri or end; 
D; posterior end; v, faces for srasaiudes. ith ve 2a Te. 
Figure 7.—Chevron = another individual ; top and side views; size and 
‘ letters as in Fig. 
