description of plates. 17i 



Plate 7. 



Fig. I . Type of Clepsydrops colletii, lumbar vertebra, lateral view, No. 6530 University of 

 Chicago. X i>^. 



2. Same, anterior view. X i^. 



3. Same, posterior view. X i/4- 



4. Clepsydrops sp., caudal vertebra from side, No. 6534 Univ. of Chicago. X Yz. 



5. Same, from below. X i>^. 



6. Clepsydrops colletii, dorsal vertebra from below, No. 6534 Univ. of Chicago. X i . 



7. Same, posterior view. X i. 



8. Same, anterior view. X i. 



9. (r/d7!'.s)'^;-^'/'jrsp., atlas, anterior view. No. 6529 University of Chicago. X lyi. 



10. Same, lateral view. X i>^. 



1 1 . Clepsydrops sp., lumbar vertebra, lateral view, No. 6534 Univ. of Chicago. X i. 



12. Same, anterior view. X i. 



13. Clipsyd/vps sp., dorsal vertebra, No. 6534 University of Chicago. X i. 



14. Clepsydrops pedunadatus, posterior lumbar vertebra, posterior view, No. 6534 



University of Chicago. X i>^. 



15. Same, lateral view. X i^. 



16. C/f/>5i'«'r(7/i5Z'zVw/wzV, axis, lateral view. No. 6532 University of Chicago. X i>^. 



17. Same, posterior view. X i>^. 



18. Clepsydrops sp., humerus, No. 6545 University of Chicago. X i. 



19. Same, humerus turned 90°. X i. 



Plate 8. 



Fig. I. Photograph of right side of skull o{ Dimetrodon incisivus, No. looi University 

 of Chicago. X y,,. 

 2. Explanatory figure of same. 



Plate 9. 



Fig. I. Lower jaw Dimetrodon incisivus. No. looi University of Chicago, inner view of 

 left ramus. X y,,. 



2. Explanatory figure of fig. i. 



3. Lower jaw Dimetrodon incisivus, No. looi University of Chicago. Outer view 

 of right ramus. X '/i?- 



4. Explanatory figure of fig. 3. 



Plate 10. 



Fig. I. Top of skull, Z?/wd'//Wc>« ?«(r«m«. No. looi University of Chicago. X about ^. 



2. Explanatory figure of same. 



3. Outer view of maxillary of Z'mif/^Wtiw iucisivus,T^o. loi 6 University of Chicago. 



4. Inner view of maxillary of Dimetrodon incisivus, No. 78 University of Chicago. 



