lyo REVISION OF THE PELYCOSAURIA. 



Plate 3. 

 Theropleura rciroversa. 



Fig. I. Quadrate and quadra to-jugal (?) of right side. X >^. 



2. Posterior view of same. X >^. 



3. Anterior end of lower jaw. X %. 



4. Articular region of left side with pterygoid. X >^. 



5. Femur and tibia. X )'2- 



6. Outer view of pelvis crushed flat. X Yi. 



7. Posterior view of femur. X %. 



Plate 4- 



Fig. I. Lateral view of an anterior vertebra, axis ?, oi Elcabrosauriis baldwhii. No. 2285 

 Am. Mus. Nat. Hist. X i- 



2. Lateral view of a dorsal of same. X i- 



3. Lateral view of a lumbar of same. X i. 



4. Lateral view of a posterior lumbar of same. X i ■ 



5. Anterior of same. X i- 



6 Archeobclus vclUcatus Cope. X 2. 



7. Skull of Clcpsydrops natalis Cope, from the right side, No. 41 10 Am. Mus. Nat. 



Hist. X I- 



8. Skull of same from left side showing the postorbital region. X i. 



Plate 5. 



Fig. I. Lumbars and anterior half of tail, Ckpsydrops natalis, No. 4110 Am. Mus. 



Nat. Hist. X I. 



2. Caudals from middle portion of tail, same. X i. 



3. Caudals from posterior portion of tail, same. X i. 



4. Upper surface of posterior foot, same. X i. 



5. Lower surface of same. X i- 



6. Upper surface of anterior foot of a small Dimetrodon, possibly D. navajovims, 



from New Mexico, No. 2290 Am. Mus. Nat. Hist. X i- 



7 Femur of Clcpsydrops natalis, from Illinois, No. 6548 Univ. of Chicago. X 



8 Vertebrseofasmall 77/£'ro/'/«/r«, from Illinois, No. 6578 Univ. of Chicago. ^ 



9 Ilium of a small Ckpsydrops (?), from Illinois, No. 6556 Univ. of Chicago. 

 ID. Ilium of a small Ckpsydrops (?), from Illinois, No. 6557 Univ. of Chicago. X i . 



Plate 6. 

 Ckpsydrops natalis Cope, No. 41 10 Am. Mus. Nat. Hist. All figures X i. 



Fig. I. Humerus. 



2 Scapula with clavicle and cleithrum (?). 



3. Left half of pelvis with femur, tibia, and fibula; limb thrown up and back. 



4. A posterior dorsal. 



5. First lumbar. 



6. Three anterior dorsals. 



I. 

 X I. 

 X I. 



