EXPLANATION OF PLATES. 



PLATE I. 



Jurassic Dinosaur, Morosaurus grandis Marsh. (One twentieth 

 natural size.) — Page 433. 



Figure 1. — Fore leg : s, scapula ; c, coracoid ; h, humerus ; r, radius ; 



u, ulna; uc, ulnar carpal ; /, first metacarpal ; Vmc, fifth metacarpal. 

 Figure 2. — Hind leg : il, ilium ; is, ischium ; p, pubis ; /, femur ; t, 



tibia ; f r , fibula ; a, astragalus ; c, calcaneum ; Vmt, fifth metatarsal. 



PLATE II. 



Jurassic Dinosaurs of the genus Apatosaurus of Marsh. — Page 433. 



Figure 1. — Cervical vertebra of the Apatosaurus laticollis 

 Marsh, back view (one sixteenth natural size) : c, posterior articular 

 surface or cup ; d, diapophysis ; p y parapophysis ; h, hatchet bone, 

 or anchylosed rib ; z', postzygapophysis ; f, lateral foramen. 



Figure 2. — Side view of same vertebra : b, anterior articular sur- 

 face ; c, posterior id. ; f, foramen in centrum ; z, prezygapophysis ; 

 z f , postzygapophysis. 



Figure 3. — Sacrum of the Dinosaur, Apatosaurus Ajax Marsh 

 (one tenth natural size) : a, anterior face of first sacral vertebra 5 

 p, posterior face of last sacral vertebra ; b, transverse process of first 

 sacral vertebra ; c, transverse process of second ; d, transverse proc- 

 ess of third ; ff f , foramina between transverse processes ; e e ( , sur- 

 faces for union with ilia. 



PLATE III. 



Jurassic Dinosaurs, Laosauridje of Marsh. — Page 433. 



Figures 1, 2. — Tooth of Laosaurus altus Marsh : front and side 



view (twice natural size). 

 Figure 3. — Hind leg of same (one eighth natural size) : letters as 



in Plate I. 

 1 For the following twelve plates this work is indebted to Prof. 0. C. Marsh. 



