J?. S. Lull — Cranial Musculature in Dinosaurs. 399 



EXPLANATION OF PLATES AND FIGURES. 



Plate I. Skull of Triceratops serratus Marsh, with jaw muscles (1/8). 



Plate II. Skull of Triceratops serratus Marsh, with neck muscles (1/8). 



Plate III. Skull of Triceratops serratus Marsh, rear view, with muscles 

 (1/8). (Blood vessel impressions indicate the free margin of the 

 . frill.) 

 Bones : ang, angular ; bo, basioccipital ; cp, coronoid process ; d, dentary ; 

 ep, epoccipital ; exo, exoccipital ; fm, foramen magnum ; fp, 

 postfrontal ; h, supraorbital horn ; j, jugal ; lac, lachrymal ; m, 

 maxillary ; n, nasal horn ; o, orbit ; oc, occipital condyle ; p, pa, 

 parietal ; pd, predentary ; pf, prefrontal ; pmx, premaxillary ; 

 qj, quadratojugal ; qu, quadrate ; r, rostral ; sang, surangular ; 

 sq, squamosal ; I, atlas ; II, axis ; III and IV, 3d and 4th 

 cervical vertebras. 

 Muscles: hue, buccinator; dm, depressor mandibuli ; ip, pterygoideus ; 

 lat, complexus minor (latissimus dorsi); He, ?levator claviculse ; 

 Ion, complexus major (longissimus dorsi) ; rb, rectus anticus 

 brevis ; rl, r.a.longus ; rma, rectus posticus major; rmi, r.p. 

 minor; t, temporalis. 



Fig. 1. Under side, rear, of lower jaw of Triceratops serratus. 



Fig. 2. Chameleo vulgaris, adapted from Parker. 



Fig. 3. Chameleo pumilis, adapted from Parker. 



Fig. 4. Torosaurus latus, skull, top view, after Marsh. 



Fig. 5. Centrosaurus apertus, frill top view, modified from Lambe. 



Fig. 6. Triceratops serratus, skull, top view, after Marsh. 



Fig. 7. Ceratops canadensis, portion of skull, side view, after Lambe. 



Fig. 8. Jguanodon bernissartensis, skull, top view, adapted from Dollo. 



Fig. 9. Trachodon mirabilis, skull, top view, after Cope. 



Fig. 10. Chameleo owenii, adapted from Metcalf. 



c, sf, supratemporal fossa ; /, paf, parietal fenestra ; shaded area, 



supratemporal fossa. 



