EXPLANATION OF PLATES 143 



same from above; Fig. 12, the same, from the side. All figures, save 5, twice 

 natural size of the embryonic specimen, and about equal to adult size. 



Plate XXX. — Craddock bone-bed. Fig. i, Clepsydrops, left femur, 

 ventral side and proximal end; Fig. 2, Clepsydrops, left femur, dorsal side; 

 Fig. 3, Clepsydrops, juvenile left femur, dorsal side; Fig. 4, gen. nov. left 

 femur, dorsal side, with proximal and distal ends; Fig. 5, Clepsydrops, juvenile 

 left humerus; Fig. 6, pariotichid genus indet., left femur, dorsal side; Fig. 7, 

 the same, ventral side; Fig. 8, gen. indet. radius; Fig. 9, gen. indet. fibula; 

 Fig. 10, Clepsydrops (?), left tibia, ventral side; Fig. 11, Clepsydrops (?), 

 fibula. 



Plate XXXI. — Craddock bone-bed. Fig. i, gen. nov. left ilium, outer 

 side; Fig. 2, Clepsydrops, left ilium, outer side; Fig. 3, Clepsydrops, right 

 humerus, ventral side; Fig. 4, Clepsydrops, left ischium; Fig. 5, Clepsydrops 

 (?), quadrate, inner side; Fig. 6, the same, distal end; Fig. 8, Clepsydrops (?) 

 articular, from above; Fig. 9, the same from below; Fig. 10, Clepsydrops, 

 fibulare. 



Plate XXXII. — Craddock bone-bed. Fig. i, Clepsydrops, femur, dorsal 

 side; Fig. 2, radius, indet.; Fig. 3, fibula, indet.; Fig. 4, Aspidosaurus, femur, 

 ventral side; Fig. 5, tibia (reversed), indet.; Fig. 6, Aspidosaurus, femur, 

 ventral side; Fig. 7, Aspidosaurus peltatus Willis ton, dorsal shield, from 

 above; Fig. 8, diadectid tooth; Fig. 9, Clepsydrops (?), astragalus, from in 

 front; Fig. 10, astragalus, indet., dorsal side; Fig. 11, fibulare, indet. 



Plate XXXIII. — Craddock bone-bed. Figs, i, 2, 3, 4, Aspidosaurus, 

 spp. femora, ventral side; Figs. 5, 6, radii, indet.; Figs. 7, 8, gen. nov. tibiae, 

 dorsal side; Fig. 9, fibula, indet. ; Fig. 10, radius, indet. ; Yig.ii, Aspidosaurus, 

 ilium, from without. 



Plate XXXIV. — ^New Mexico, Yale collections. Fig. i, Sphenacodon 

 ferox Marsh, type, left dentary, from without; Fig. 2, Sphenacodon ferox, left 

 premaxilla, from within; Fig. 3, Ophiacodon mirus Marsh, tjrpe, right dentary, 

 from without; Fig. 4, Ophiacodon, right clavicle, external side; Fig. 5, Nothodon 

 lentus Marsh, type, left dentary, from the side; Fig. 6, the same, from above; 

 Fig. 7, Nothodon lentus, posterior tooth, from behind; Fig. 8, Eryops, ungual 

 phalanx; Fig. 9, Eryops, sacral rib; Fig. 10, Ophiacodon ( ?), right neural arch of 

 atlas; Fig. 11, the same, from without. 



Plate XXXV. — ^New Mexico, Yale collections. Fig. i, Nothodon lentus 

 Marsh (probably, with the three following, a part of type specimen), left radius, 

 with proximal end; Fig. 2, N. lentus, left ulna, ventral side; Fig. 3, N. lentus, 

 left fibula, ventral side; Fig. 4, N. lentus, left tibia, dorsal side, with a, proximal 

 end; Fig. s, Sphenacodon (?) Ophiacodon (?), right himierus, ventral side; 

 Fig. 6, Ophiacodon, tibia; Fig. 7, Ophiacodon (?), fibula; Fig. 8, Ophiacodon, 

 left ulna, ventral side; Fig. 9, the same, dorsal side; Fig. 10, Ophiacodon, 

 radius; Fig. 11, the same, ulnar side. Figures two-thirds natural size. 



Plate XXXVI. — ^New Mexico, Yale collections. Fig. i, Platyhystrix 



